Feline Chronic Gingivostomatitis
FCGS, Caudal stomatitis, Feline chronic gingivitis-stomatitis, Lymphoplasmacytic stomatitis, Feline stomatitis, Caudal oral stomatitis
Feline chronic gingivostomatitis is long-lasting, severe inflammation of the soft tissue inside a cat's mouth. The worst of it is usually far back in the mouth, where the upper and lower jaws meet, and the tissue there becomes red, swollen, ulcerated and extremely sore. It is one of the most painful conditions cats get, which is why affected cats drool, paw at their face, cry at the food bowl, stop grooming and lose weight. You and your children cannot catch this. The condition itself is not passed from cat to cat, but the calicivirus commonly found alongside it can be - so if you have other cats, mention that to your vet. And it is treatable. Finding out what is really going on needs a look at the very back of the mouth under GENERAL ANAESTHESIA (not light sedation, and not an awake exam) with X-rays of every tooth; most cats then improve a great deal once the teeth in the inflamed areas are removed, though some need medicine afterward as well. One thing every owner facing that decision deserves to hear: CATS EAT WELL WITHOUT TEETH, dry food included. Losing teeth is not losing quality of life. Three warnings before you try anything at home. (1) NEVER give your cat human pain medicine. Acetaminophen, also sold as paracetamol or Tylenol, can kill a cat with a single tablet, and ibuprofen (Advil), naproxen (Aleve) and aspirin cause stomach ulcers and kidney failure in cats at doses people think are trivial - human cold and flu medicines count too, because many of them contain acetaminophen. (2) NEVER give a cat medicine prescribed for a dog or for another cat; dog anti-inflammatories are especially dangerous in cats, because a cat's liver cannot process many drugs a dog handles safely. (3) NEVER put a human mouth gel, rinse, spray, numbing product or home remedy into your cat's mouth - nothing goes in that mouth except what the vet treating this cat has prescribed for this cat. And if your cat is already on medicine for this, CALL YOUR CLINIC BEFORE YOU CHANGE ANYTHING - before you stop it, skip it, split it, double it, restart it, or add anything you bought yourself.
What you might notice
- Drooling, sometimes thick, ropey, or tinged pink with blood
- Pawing at the mouth or face, or rubbing the face along furniture
- Walking up to the food bowl hungry, then crying out, flinching, or running away
- Dropping food, chewing on only one side, or swallowing dry food whole without chewing
- Strong, foul breath that is new or getting worse
- Coat looks matted, greasy, or unkempt because grooming hurts too much
- Steady weight loss even though your cat still seems interested in food
- Hiding more, snapping when touched near the head, or refusing to be petted on the face
Standard of care
Assess the mouth properly - which means under general anaesthesia, with full-mouth intraoral radiographs
Approved / guideline-backedA conscious examination can suggest FCGS but cannot stage it. The caudal oral cavity, the mucosa behind the last molars, the palatoglossal folds and the roots of every tooth must be examined under general anaesthesia with full-mouth intraoral dental radiographs, and findings must be charted. This visit is also when a biopsy is taken from any lesion that is unilateral, asymmetric, unusually proliferative, or not responding as expected, because squamous cell carcinoma, eosinophilic disease and lymphoma can all mimic FCGS. PLAN THE ANAESTHETIC AROUND THE CAT, NOT THE CALENDAR: many FCGS cats present inappetent, dehydrated and sometimes azotaemic, and such a cat is stabilised first - intravenous fluids, electrolyte correction, pre-anaesthetic CBC, serum biochemistry and urinalysis, plus total T4 in cats aged 7 years and over - with multimodal analgesia and perioperative parenteral fluids planned for the procedure itself. Stabilising is not postponing: delay is its own harm in this disease, so the procedure is booked with a stabilisation plan attached rather than performed on whatever condition the cat happens to arrive in. No product, rinse, gel, supplement, cell therapy or injection is a substitute for this step, and PetSmartMeds must never be positioned as an alternative to it.
Named products: No therapeutic drug at this step. Anaesthetic and analgesic protocol per the 2025 FelineVMA guidelines and the 2022 ISFM acute pain guidelines.
The 2025 FelineVMA feline oral health and dental care guidelines are a Practice Guideline authored by a task force of board-certified veterinary specialists and a veterinary technician specialist in dentistry, and they cover feline chronic gingivostomatitis explicitly among the commonly encountered feline oral and dental diseases. The guidelines state that while patient assessment begins with examination of the conscious cat, further assessment under anaesthesia is necessary for radiography and treatment, making anaesthesia an essential component of feline dentistry. The 2019 AAHA Dental Care Guidelines provide the same requirement for both species.
Treat the pain from the first visit, with feline-specific drugs only
Approved / guideline-backedFCGS is among the most painful conditions in feline practice, and pain control is not an optional add-on to be started after the dental procedure. Multimodal perioperative analgesia and anaesthesia are standard features of feline oral and dental care per the 2025 FelineVMA guidelines. Route matters in this disease: forcing a painful mouth open twice daily for an oral tablet is itself a welfare problem, so injectable and transdermal options and highly palatable liquid formulations deserve preference. Pain in cats is historically under-recognised and under-treated, and validated feline pain assessment tools exist but are under-used. THREE RULES THAT KEEP A PAINFUL CAT ALIVE, AND THEY BELONG IN THE OWNER CONVERSATION ON DAY ONE. (1) NEVER give a cat a human analgesic: acetaminophen/paracetamol can kill a cat at a single human tablet, and ibuprofen, naproxen and aspirin cause gastrointestinal ulceration and acute kidney injury at ordinary human over-the-counter doses. (2) NEVER carry a canine drug, dose or product across to a cat - a canine NSAID is not a feline NSAID at a smaller number of milligrams. (3) NEVER combine an NSAID with a corticosteroid. The ONSIOR (robenacoxib) label states 'Do not administer ONSIOR tablets or injection in conjunction with any other oral or injectable NSAID or corticosteroid' and directs that appropriate washout periods be considered when switching from one NSAID to another or from corticosteroid use to NSAID use. That prohibition is load-bearing on this page specifically, because prednisolone appears further down it. The inappetent, dehydrated FCGS cat is also the patient the ONSIOR label names as highest risk - 'Patients at greatest risk for adverse events are those that are dehydrated, on concomitant diuretic therapy, or those with existing renal, cardiovascular, and/or hepatic dysfunction' - so hydration status and renal function are assessed before an NSAID is given, and parenteral fluids are recommended during surgery. FINALLY, CALL BEFORE YOU CHANGE ANYTHING: analgesia in this disease is managed at home for weeks, and an owner must never stop, skip, split, double, restart or supplement a dose without speaking to the clinic first.
Named products: Buprenorphine has two FDA-approved feline products, both labelled for control of postoperative pain associated with surgical procedures in cats, and both DEA Schedule III controlled substances: SIMBADOL (buprenorphine injection, NADA 141-434), whose label states 'Do not dispense SIMBADOL for administration at home by the pet owner' and which has not been evaluated in cats younger than 4 months or in breeding, pregnant or lactating cats; and ZORBIUM (buprenorphine transdermal solution, 20 mg/mL, NADA 141-547), labelled for cats at least 4 months of age weighing 2.6-16.5 lb (1.2-7.5 kg), where a single topical application provides analgesia for 4 days. ZORBIUM's human-safety directions are mandatory, not advisory: 'Wear impermeable latex or nitrile gloves, protective glasses, and a laboratory coat to prevent direct solution contact with human skin, eyes, or mucosa when handling and applying the solution'; allow a minimum drying time of 30 minutes before direct contact with the application site; and 'Accidental exposure to even one tube of ZORBIUM, especially in children, can result in a fatal overdose of buprenorphine' - so children and other pets must be kept away from a freshly dosed cat's application site. Robenacoxib (ONSIOR) is FDA-approved in US cats ONLY for control of postoperative pain and inflammation associated with orthopaedic surgery, ovariohysterectomy and castration, in cats at least 5.5 lb (2.5 kg) and at least 4 months of age, for a MAXIMUM OF 3 DAYS; it is contraindicated in cats hypersensitive to robenacoxib or with known NSAID intolerance, must not be given with any other NSAID or with a corticosteroid, 'has been shown to prolong the QT interval' (concurrent QT-prolonging drugs such as antihistamines, prokinetics and certain anaesthetics are not recommended), has been associated with 'seizures, ataxia, and nystagmus', and has not been studied in cats with cardiac disease. A cat whose FCGS has taken it below 2.5 kg, or a kitten under 4 months, is outside that label altogether - and an underweight cat cannot be dosed accurately. Any longer or different use is extralabel, is a veterinarian's decision inside a valid veterinarian-client-patient relationship, and must never be advertised (21 CFR 530.4). ACETAMINOPHEN (PARACETAMOL) IS ABSOLUTELY CONTRAINDICATED IN CATS AT ANY DOSE, AND IBUPROFEN, NAPROXEN AND ASPIRIN MUST NEVER BE GIVEN TO A CAT EITHER. Label sources: DailyMed SPLs for SIMBADOL (buprenorphine) injection, Zoetis Inc.; ZORBIUM (buprenorphine) solution, Elanco US Inc.; ONSIOR (robenacoxib) tablet, Elanco US Inc.
Guideline-backed, with FDA-approved feline analgesics available. The 2022 ISFM Consensus Guidelines on the Management of Acute Pain in Cats note that the unique challenges of feline metabolism and comorbidities may lead to undertreatment of pain. The 2025 FelineVMA guidelines state that feline patients with oral and dental disease, and those convalescing from surgery, generally experience pain and that multimodal perioperative analgesia and anaesthesia are standard features of care.
Extract the teeth in the areas of inflammation - this is the primary treatment and it works in about two-thirds of cats
Approved / guideline-backedRemoval of the teeth adjacent to inflamed tissue, with complete extraction of all root material confirmed radiographically, is the treatment with the best outcome data in FCGS. Partial-mouth (premolar-molar) extraction and full-mouth extraction had equivalent outcomes in the two largest series, so full-mouth extraction should not be presented to owners as automatically superior. Retained root fragments are a recognised cause of persistent inflammation, which is why intraoral radiographs before and after extraction are part of the procedure rather than an extra. Cats eat well without teeth, including dry food; loss of teeth is not loss of quality of life, and this is the single most important reassurance to give an owner facing this decision.
Named products: Surgical, not pharmacological. Antimicrobials are not a treatment for FCGS - note that in Jennings et al. the cats who did NOT need follow-up antimicrobials had the better long-term outcome (OR 3.7).
Retrospective case series, n=95 cats, median postoperative follow-up 231 days (range 33-2,655). Following tooth extraction, 27/95 (28.4%) had complete resolution of stomatitis and 37/95 (39.0%) had substantial clinical improvement; 25/95 (26.3%) had little improvement and 6/95 (6.3%) had none. Of the 64 cats with a positive outcome, 44 (68.8%) required extended medical management for a finite period to achieve it. Extent of extraction (partial-mouth vs full-mouth) was NOT associated with overall response. Better long-term response was predicted at the first recheck by resolution of abnormal behaviour (OR 7.2), decrease in oral inflammation (OR 3.5), and lack of need for follow-up antimicrobials (OR 3.7). An independent series of 104 FCV-positive FCGS cats (56 with rechecks) reported clinical cure in 32.1% and very significant improvement in 19.6%, i.e. 51.8% within 38 days, with 60.7% of owners considering their cat cured or significantly improved, and again found extent of extraction did not influence outcome.
For cats still painful after extraction: ciclosporin, dosed to a measured blood trough
Controlled trial in this speciesRoughly a quarter to a third of cats remain refractory after extraction and need medical management. Ciclosporin (cyclosporine) has the only randomised, placebo-controlled, double-blinded drug trial in this exact population. The trial's most useful practical finding is that response tracked the measured drug concentration, not the milligram dose - individual absorption varied by nearly fifty-fold - so trough whole-blood monitoring is part of the therapy rather than an optional refinement. This is EXTRALABEL use: the only FDA-approved feline ciclosporin product, ATOPICA for Cats (cyclosporine oral solution, NADA 141-329), is approved for control of feline allergic dermatitis, not for stomatitis. Extralabel use is a veterinarian's judgement within a valid veterinarian-client-patient relationship under 21 CFR Part 530, and 21 CFR 530.4 forbids any seller from promoting an extralabel use - PetSmartMeds may describe this evidence as education and must never advertise it. BEFORE THE FIRST DOSE, NOT AFTER IT: test FeLV and FIV and do not start an immunosuppressant blind, because the approved feline label contraindicates use in retrovirus-infected cats; and biopsy any lesion that could be neoplastic, because the same label contraindicates use in cats with a history of or suspected malignancy and because suppressing the immune system of a cat that actually has oral cancer is worse than not treating it. WHILE THE CAT IS ON IT: keep it strictly indoors, feed no raw or undercooked meat, and prevent hunting and scavenging, because a Toxoplasma-seronegative cat that becomes infected during treatment can develop clinical toxoplasmosis that may be fatal; report lethargy, fever, breathing difficulty, vomiting, diarrhoea or any neurological or behavioural change the SAME DAY; expect a reduced response to vaccination and ask the veterinarian before any vaccine, particularly a modified-live one; weigh the cat at every visit, because progressive weight loss resulting in hepatic lipidosis occurred in 2 of 205 cats in the approved product's field study; and do not add a corticosteroid or any other immunosuppressant alongside it. CALL BEFORE YOU CHANGE ANYTHING: this drug is given at home, absorption varies nearly fifty-fold between cats, and the dose is set against a measured blood trough - so an owner must never adjust, stop, restart, split or double a dose, or change how it is given with food, without speaking to the clinic first.
Named products: Ciclosporin / cyclosporine. ATOPICA for Cats (cyclosporine oral solution) NADA 141-329 - approved indication is 'Control of feline allergic dermatitis as manifested by excoriations (including facial and neck), miliary dermatitis, eosinophilic plaques, and self-induced alopecia in cats at least 6 months of age and at least 3 lbs (1.4 kg) in body weight.' Its label CONTRAINDICATES use in cats with a history of malignant disorders or suspected malignancy, in cats infected with FeLV or FIV, and in cats hypersensitive to cyclosporine. See the safety section before any cat is started on it.
Randomised, placebo-controlled, double-blinded clinical study in 16 cats with chronic stomatitis that had previously undergone premolar-molar or full-mouth extractions. Cyclosporine 2.5 mg/kg or placebo orally twice daily; scored every 2 weeks for 6 weeks on a 30-point Stomatitis Disease Activity Index (SDAI). Mean SDAI improvement at 6 weeks was 52.7% in the treatment group versus 12.2% in placebo (significant). 7/9 treated cats (77.8%) achieved >40% SDAI improvement versus 1/7 placebo cats (14.3%) (significant). Trough whole-blood cyclosporine ranged from 32.1 to 1,576.2 ng/mL; cats with trough >300 ng/mL improved 72.3% versus 28.2% for cats <300 ng/mL (significant). Limitations to state alongside these numbers: n=16 total, 6-week duration only, single investigator, and no long-term or relapse data.
Oromucosal recombinant feline interferon-omega - an unlabelled use of a product that has no FDA approval in the United States
Controlled trial in this speciesRecombinant feline interferon-omega given onto the oral mucosa has a randomised, multi-centre, controlled, double-blind trial in refractory FCV-positive cats with caudal stomatitis, compared against oral prednisolone rather than against placebo. This is a real within-species controlled trial and should be reported as such - but read the result precisely: the interferon arm improved significantly from baseline over 90 days while the prednisolone arm did not, yet the two arms did not differ significantly from each other on most parameters, differing only on pain at days 60 and 90. TWO SEPARATE LIMITS, AND THEY MUST NOT BE BLURRED TOGETHER. First, JURISDICTION: recombinant feline interferon-omega is authorised in the European Union by the EMA (Virbagen Omega, EMEA/V/C/000061, active substance 'recombinant omega interferon of feline origin', status Authorised) and is licensed in Japan; it is NOT FDA-approved in the United States for any indication - a DailyMed search returns no interferon-omega record at all. Never write 'approved' without naming the regulator, and never offer or imply US availability. Second, INDICATION: FCGS is not a labelled indication on any interferon-omega product label we were able to verify, and the trial's oromucosal route and 0.1 MU daily regimen are not a labelled route or regimen for stomatitis. So even where the product is legally available, this is an unlabelled use resting on one 39-cat active-comparator trial. It is a veterinarian's judgement inside a valid veterinarian-client-patient relationship, and 21 CFR 530.4 forbids any seller promoting an extralabel use - so PetSmartMeds may describe this evidence as education and must never advertise, offer or recommend it. HONEST LIMITATION: we could not retrieve the current EU summary of product characteristics (the EMA has discontinued publication at the old EPAR address), so we publish no characterisation of what the EU licence DOES cover - only that FCGS is not among the indications we could verify.
Named products: Recombinant feline interferon-omega (rFeIFN-omega), oromucosal, 0.1 MU daily in the cited trial. EMA-authorised in the European Union as Virbagen Omega (EMEA/V/C/000061) and licensed in Japan; NO FDA approval located for the United States for any indication (DailyMed: zero records for interferon omega). FCGS is not a labelled indication we could verify anywhere, so this is an unlabelled use of a product that is unavailable in the US - describe it, never promote or offer it (21 CFR 530.4). A separate feline interferon-omega clinical literature exists for retroviral disease and was NOT read in this research - publish no efficacy claim outside the FCGS trial cited here, and no characterisation of the EU licensed indications until the SPC text has been read.
Randomised, multi-centre, controlled, double-blind study in 39 cats. Daily oromucosal 0.1 MU recombinant feline interferon-omega versus oral glucocorticoid (prednisolone); behavioural, clinical and lesional scores followed to day 90. The interferon arm showed significant improvement in clinical lesions (caudal stomatitis and alveolar/buccal mucositis) and a decrease in pain scores from day 0 to day 90; no such statistical improvement was seen in the prednisolone arm; however there was no significant difference between the two groups for most parameters, except pain at days 60 and 90. Limitations: n=39, active comparator with no placebo arm, FCV-positive refractory cats only, and 90-day follow-up.
Glucocorticoids: commonly used, weakly supported, and only ever prednisolone in a cat
Early evidenceSystemic corticosteroids are widely prescribed for FCGS and often produce short-term comfort, but the controlled feline evidence for them in this disease is weak: in the only randomised trial that included a prednisolone arm, that arm did not achieve statistically significant improvement over 90 days. They remain a legitimate clinical tool for a painful cat, particularly short term while other therapy takes effect, but they should not be framed as a long-term solution, and they should never be used to postpone the anaesthetised dental procedure that actually changes the disease. Two feline-specific dosing rules matter. First, use PREDNISOLONE, not prednisone: a single 2 mg/kg oral dose of prednisolone produced roughly 4-fold higher plasma prednisolone AUC than the same dose of prednisone in cats, confirming low comparative bioavailability of oral prednisone. Second, dose to lean or ideal body weight: over-conditioned cats reached approximately 2-fold higher plasma drug concentrations than normal-conditioned cats, which may explain their increased risk of glucocorticoid-associated hepatic lipidosis and diabetes mellitus. Corticosteroids and ciclosporin should not be combined casually - the Atopica for Cats label states it is not for use with other immunosuppressive agents. NEVER WITH AN NSAID. The ONSIOR (robenacoxib) label states 'Do not administer ONSIOR tablets or injection in conjunction with any other oral or injectable NSAID or corticosteroid,' and directs that appropriate washout periods be considered when switching from corticosteroid use to NSAID use - so a cat cannot be on a feline NSAID for perioperative pain and a glucocorticoid for inflammation at the same time, and the switch in either direction needs a washout set by the veterinarian. THE RISK SIDE, AT FULL STRENGTH, BECAUSE THE FCGS EFFICACY EVIDENCE IS TIER 3: glucocorticoids in cats can precipitate congestive heart failure in a cat with occult cardiac disease, cause insulin resistance and iatrogenic diabetes mellitus, contribute to hepatic lipidosis in an inappetent cat, cause systemic immunosuppression with opportunistic infection, and produce iatrogenic hyperadrenocorticism with fragile skin on prolonged use. A course is tapered and stopped under veterinary direction - an owner must call before changing or stopping it.
Named products: Prednisolone (not prednisone) in cats. No FDA-approved veterinary glucocorticoid product carries an FCGS indication, so this is extralabel use of an approved drug under 21 CFR Part 530 and must not be promoted (21 CFR 530.4).
Pharmacology is Tier 2 within species: two-drug crossover trial in 11 clinically healthy cats (5 normal-conditioned, 6 over-conditioned) with a 3-week washout, plasma prednisolone and prednisone by HPLC; oral prednisolone 2 mg/kg gave ~4-fold higher AUC than prednisone, and over-conditioned cats had ~2-fold higher concentrations. Efficacy in FCGS specifically is Tier 3: no placebo-controlled corticosteroid trial in FCGS was located, and the prednisolone comparator arm in Hennet et al. 2011 did not reach statistical improvement from baseline. The 2016 systematic review of FCGS management found a lack of consistency between articles' data, rendering direct comparison of results unreliable, and called for standardised semi-quantitative scoring and longer follow-up.
Feed, weigh, and keep feeding - nutritional support is treatment, not aftercare
Approved / guideline-backedA cat with FCGS is a cat in pain that has to use its mouth to survive. Weight is the most honest single number in this disease, and it should be recorded at every single visit alongside body condition score. Warmed, blended, highly palatable food, wide shallow bowls, and softened or liquid diets reduce the mechanical pain of eating. A cat that has not eaten for 24 hours needs intervention rather than encouragement, and assisted feeding is a legitimate, welfare-improving intervention rather than an admission of failure. THE PATHWAY, IN ORDER: warmed and blended or liquidised food offered from a wide shallow dish; then syringe or assisted feeding of a convalescence diet; then a naso-oesophageal tube for short-term support; then an OESOPHAGOSTOMY FEEDING TUBE, which is the mainstay for a severely affected cat through the peri-extraction period because it bypasses the painful mouth entirely and lets food, water and oral medication be given without touching the ulcerated mucosa. A feeding tube in this disease buys the cat calories, comfort and compliance at once, and owners should be offered it early rather than as a last resort. Weight gain is also the cleanest marker of real response: in the one-year follow-up of the largest cell-therapy cohort, 69% of cats gained weight with a mean increase of 16.2%.
Named products: No drug required. Appetite stimulants are outside the located FCGS evidence base; capromorelin (Elura) is FDA-approved only for management of weight loss in cats with chronic kidney disease and must not be cross-sold into FCGS as though it were indicated.
Guideline-backed. The 2022 ISFM Consensus Guidelines on Management of the Inappetent Hospitalised Cat set out nutritional assessment, assisted feeding routes and feeding-tube indications for cats that will not eat.
What NOT to do: do not delay the dental procedure with products, and do not treat FCGS with antibiotics
Approved / guideline-backedTwo failure modes cause real harm in this disease, and PetSmartMeds must name both. (1) Delaying anaesthetised assessment and extraction while trying rinses, gels, supplements, lasers, biologics or a course of antibiotics leaves a cat in severe pain for weeks to months, and in the one trial that tested cell therapy BEFORE full-mouth extraction there was no clinical response in 3 of 5 cats, only a mild response in 2, and no measurable immune modulation at all - the investigators explicitly do not recommend it in that sequence. (2) Antimicrobials do not treat FCGS. In the 95-cat extraction series, cats who did NOT require follow-up antimicrobials had a 3.7-times greater odds of good long-term response - antibiotic need was a marker of a worse course, not a therapy for it. Antibiotics remain appropriate for a defined bacterial infection diagnosed by a veterinarian, and for nothing else here. (3) A THIRD FAILURE MODE BELONGS WITH THEM, BECAUSE IT HAPPENS AT HOME TONIGHT: reaching into the human medicine cabinet. No human analgesic (acetaminophen/paracetamol, ibuprofen, naproxen, aspirin, or any cold or flu preparation containing them), no medicine dispensed for a dog or for another cat, and no human mouth gel, numbing spray, antiseptic rinse or home remedy goes into a cat with this disease. If it already has, that is a poisoning emergency, not a wait-and-see.
Named products: None to give. This step is a prohibition, not a prescription: no antimicrobial as FCGS therapy, no cell or exosome product before extraction, no human analgesic, no canine medicine, and nothing applied inside the mouth that was not prescribed for this cat.
Direct feline trial evidence for the sequencing rule: 5 client-owned FCGS cats that had NOT undergone full-mouth extraction received two IV injections of 20 million fresh allogeneic or autologous adipose-derived MSC; 4 completed and 1 exited at 3 months; no positive clinical response in 3 cats, mild response in 2, and none of the cats exhibited immune modulation (no alteration in circulating CD8+ T cells, no normalisation of the CD4:CD8 ratio, no change in neutrophil counts). Authors verbatim: 'the systemic administration of ASCs prior to full-mouth tooth extraction lacks substantial clinical efficacy and is not recommended at this time.' The antibiotic point is from the multivariable analysis in Jennings et al. 2015 (OR 3.7 for better long-term response where follow-up antimicrobials were not needed).
2025 FelineVMA feline oral health and dental care guidelines - the current cat-specific document, which covers feline chronic gingivostomatitis explicitly; with the 2019 AAHA Dental Care Guidelines for Dogs and Cats as the cross-species framework and the 2022 ISFM acute pain guidelines for analgesia — Feline Veterinary Medical Association (FelineVMA); American Animal Hospital Association (AAHA); International Society of Feline Medicine (ISFM). The WSAVA Global Dental Guidelines cover the same ground for international readers (https://wsava.org/global-guidelines/dental-guidelines/).
How it is diagnosed
- Conscious oral examination to document the distribution of inflammation. FCGS is characteristically BILATERAL and worst caudally, in the palatoglossal folds and the mucosa behind the last molars, often with alveolar and buccal mucositis. A lesion that is unilateral, asymmetric, markedly proliferative, or centred on one tooth is a reason to suspect something else and to biopsy.
- General anaesthesia with FULL-MOUTH INTRAORAL DENTAL RADIOGRAPHS and a completed dental chart. The 2025 FelineVMA guidelines make anaesthetised assessment an essential component of feline dentistry; radiographs identify tooth resorption, retained roots, endodontic disease and alveolar bone loss that change the surgical plan. Photographs at this visit become the baseline against which every later recheck is judged.
- Incisional biopsy and histopathology of any atypical lesion, to exclude oral squamous cell carcinoma, eosinophilic disease and lymphoma. Histology of FCGS itself is lymphoplasmacytic mucositis, with heavy B-cell infiltration alongside CD4+ and CD8+ T cells on immunohistochemistry (Vapniarsky et al. Front Vet Sci. 2020;7:310. PMID 32582783. DOI 10.3389/fvets.2020.00310); one research group has described the disease as similar to human oral lichen planus (Arzi et al. Stem Cells Transl Med. 2017;6(8):1710-1722. PMID 28618186. DOI 10.1002/sctm.17-0035) - a described similarity, not an established equivalence. Biopsy is also how response is confirmed objectively in the published trials.
- FeLV and FIV testing. This is not optional if immunosuppression is being considered: the approved feline ciclosporin label contraindicates use in FeLV- or FIV-infected cats. Retroviral status also reframes prognosis and infection risk.
- CBC, serum biochemistry and total protein with globulins, plus urinalysis; total T4 in cats aged 7 years and over. Hyperglobulinaemia and neutrophilia are markers of more severe systemic inflammation and, in the UC Davis series, predicted NON-response to cell therapy; a fall in globulins accompanied response. Renal and thyroid screening governs anaesthetic and analgesic choices in senior cats.
- Feline calicivirus PCR on an oropharyngeal swab - optional, and interpret cautiously. FCV was detected in 60.0% of FCGS cats versus 24.0% of controls (PMID 28235708), but in 104 FCV-positive FCGS cats the oral FCV load was NOT associated with signalment, history, preoperative treatment, or caudal and alveolar stomatitis severity, and did NOT predict outcome after extraction; only the presence of lingual ulcers correlated with FCV load (p=0.0325) (PMID 29270412). A positive result does not change the surgical plan and a negative result does not exclude FCGS. Do not sell a test that does not change management.
- Baseline Stomatitis Disease Activity Index (SDAI) score, body weight, body condition score and a validated pain assessment, recorded before any treatment. Without a baseline number and baseline photographs, no later claim of improvement is verifiable - by an owner, by a clinician, or by us.
Where a biologic fits
Our own product, graded by the same rule
Feline chronic gingivostomatitis is one of the few feline diseases in which intravenous cell therapy has reached multi-site clinical trials: across four studies with no concurrent control arm - two pilot case series of 9 and 7 cats, an NIH-funded 18-cat multicentre study, and a 46-cat industry-sponsored (Gallant) baseline-controlled field trial, totalling roughly 80 cats that remained painful after tooth extraction - 57-79% improved on owner or clinician assessment, a minority reached complete remission lasting up to two years, and one-year follow-up of the largest cohort reported no immunogenic or tumorigenic safety concerns; but none of those positive studies had a placebo group, veterinarian-assessed lesion healing ran about 30 percentage points below owner-reported success, the only randomised placebo-controlled trial (16 cats, a single dose of xenogeneic EQUINE cells) found no benefit at all while no feline-derived cell product has ever been tested against placebo, cells given before extraction instead of after produced no response and no immune change, and no cell, exosome or peptide product for cats is approved by the FDA in the United States or authorised by the EMA in the European Union, and in the US such products are unapproved new animal drugs - so this is a salvage option for refractory cats after extraction that a veterinarian may discuss with you, never a replacement for the dental surgery, and never a first step.
What exists
FELINE, LIVE MESENCHYMAL STROMAL CELLS, INTRAVENOUS, AFTER EXTRACTION. Five reports, NONE with a concurrent control arm, covering roughly 80 distinct cats - report (5) below is the one-year extension of report (4)'s cohort, not a further group of cats, so the numbers must not be added together. NO SUPERLATIVE IS PUBLISHED HERE. Whether this is the 'best-studied' or 'deepest' regenerative programme in veterinary medicine cannot be checked against any source, and the authoritative 2026 review points the other way: it locates the most robust veterinary MSC data in equine superficial digital flexor tendon injury and in osteoarthritis of dogs and horses, with other conditions resting on pilot studies, case series or single trials (Zayed M, Jeong BH. Vet J. 2026;320:106837. PMID 42624276. DOI 10.1016/j.tvjl.2026.106837). The countable fact is the one to publish: FCGS is one of the few feline diseases in which intravenous MSC therapy has reached multi-site clinical trials. (1) UC Davis, fresh AUTOLOGOUS adipose-derived MSC (ASC): 9 cats with refractory FCGS enrolled, 7 completed; two IV injections of 20 million autologous ASC one month apart; oral biopsies at 0 and 6 months. 5/7 responded - 3 complete clinical remission, 2 substantial clinical improvement, 2 non-responders. Responders showed systemic immunomodulation: decreased circulating CD8+ T cells, normalised CD4/CD8 ratio, decreased neutrophil counts, decreased IFN-gamma and IL-1beta, and a temporary rise in IL-6 and TNF-alpha. No clinical recurrence after complete remission over 6-24 months of follow-up. Candidate predictive biomarker: cats with <15% cytotoxic CD8 T cells with low CD8 expression (CD8lo) were 100% responsive; cats with >15% CD8lo were non-responders. Arzi B, Mills-Ko E, Verstraete FJM, Kol A, Walker NJ, Badgley MR, Fazel N, Murphy WJ, Vapniarsky N, Borjesson DL. Stem Cells Transl Med. 2016;5(1):75-86. PMID 26582907. DOI 10.5966/sctm.2015-0127. (2) UC Davis, fresh ALLOGENEIC ASC - weaker than autologous: 7 cats, same two-dose 20 million IV regimen, radiolabelled cells tracked systemically. 4/7 (57%) responded - 2 complete remission, 2 substantial improvement, 3 non-responders. Clinical remission took up to 20 months, with no relapse. Non-responders had more severe systemic inflammation before therapy (neutrophilia, hyperglobulinaemia, higher IFN-gamma and TNF-alpha). A higher fraction of radiolabelled ASC localised to the oral cavity of FCGS-affected cats than of the control cat. Authors' own verdict: allogeneic ASC 'appeared to have lower clinical efficacy with a delayed response as compared to the fresh, autologous ASCs.' Arzi B, Clark KC, Sundaram A, Spriet M, Verstraete FJM, Walker NJ, Loscar MR, Fazel N, Murphy WJ, Vapniarsky N, Borjesson DL. Stem Cells Transl Med. 2017;6(8):1710-1722. PMID 28618186. DOI 10.1002/sctm.17-0035. (3) NIH-funded multicentre shipping study: 18 FCGS cats enrolled at UC Davis and several other US sites to test whether fresh ASC could be shipped to distant clinics. Cells retained viability, phenotype and function after shipment; 72% positive response rate, 'identical to that noted in our previous studies'. Responders had a significant decrease in circulating globulin, histological decrease in oral mucosal CD3+ T cells and CD20+ B cells, and significantly decreased blood CD8 percentages. Arzi B, Peralta S, Fiani N, Vapniarsky N, Taechangam N, Delatorre U, Clark KC, Walker NJ, Loscar MR, Lommer MJ, Fulton A, Battig J, Borjesson DL. Stem Cell Res Ther. 2020;11(1):115. PMID 32169089. DOI 10.1186/s13287-020-01623-9. (4) The largest and most recent - allogeneic UTERINE-derived MSC (UMSC), sponsor-run, multi-site, BASELINE-CONTROLLED (explicitly no placebo arm): 46 cats with refractory FCGS after partial- or full-mouth extractions, two IV doses of 20 million UMSC 14 days apart, 90-day prospective design. Treatment success at days 28 / 60 / 90 was 61.4% (27/44), 76.3% (29/38), 78.8% (26/33) for client-specific outcome measures (CSOM, owner-scored); 65.9% (29/44), 73.7% (28/38), 75.8% (25/33) for owner-reported overall response (ORA); and 31.8% (13/44), 47.5% (18/38), 45.5% (15/33) for the veterinarian-assessed global oral lesion score (GOLS). After a single dose at day 14: CSOM 52.3% (23/44), GOLS 25.0% (11/44). Cats treated within 6 months of tooth extraction had greater GOLS improvement. No statistically significant difference between partial- and full-mouth extraction cats. Adverse events were 'generally mild and transient, with most related to underlying disease'; all six serious adverse events were 'either unlikely to be due to, or in one case inconclusively attributed to, UMSC therapy'. Sponsor: Gallant / Gallant Therapeutics, San Diego, with UC Davis VIRC co-authors. Williams VS, Schneider JL, Parrish RS, Thompson CM, Wrightson C, Taechangam N, Sharif O, Soltero-Rivera M, Arzi B, Black L. J Feline Med Surg. 2025;27(11). PMID 40999564. DOI 10.1177/1098612X251385852. (5) One-year open-label safety extension of that cohort, 35 cats to day 365 with NO additional UMSC dosing and concomitant medications permitted. Safety is the primary and strongest result: no serious adverse events associated with UMSC administration, no clinically relevant haematology or urinalysis abnormalities, and 'no reported immunogenic or tumorigenic safety concerns'. Most common adverse events temporally associated with dosing were transient nausea, vomiting, tachypnoea, diarrhoea, hypersalivation and pyrexia. At one year: 69% of cats gained weight (mean +16.2%); ORA improvement 75.8% at day 180 and 65.6% at day 365; GOLS improvement 51.5% at day 180 and 46.9% at day 365; mean lesion-score reduction 33%; 22% achieved clinical cure; 66% did not restart medical therapy and only 8.6% continued an immunosuppressant. Williams VS, et al. J Feline Med Surg. 2026;28(4). PMID 41757710. DOI 10.1177/1098612X261431058. INDEPENDENT APPRAISAL: an RCVS Knowledge Summary reviewed five interventional studies and graded the strength of evidence 'Moderate' - the highest grade awarded to any companion-animal cell-therapy indication - with the clinical bottom line that IV MSC therapy 'is safe to administer and can be effective in remission or alleviating the clinical signs of refractory, chronic gingivostomatitis in cats that have undergone full-mouth tooth extraction', and the explicit caveat that 'conducted clinical trials are prone to different degrees of bias due to the lack of independent control groups, the small number of subjects, and enrolling subjects with various severity of the disease.' Nekouei O, Wong ST, Leung TKY, Ngai QA, Wong WS, Almendros A. Vet Evid. 2024;9(1). PMID 42005358. DOI 10.18849/ve.v9i1.680. That appraisal predates the null randomised trial below. THE NULL RANDOMISED PLACEBO-CONTROLLED TRIAL, WHICH MUST BE DISCLOSED ALONGSIDE EVERY RESPONSE-RATE FIGURE ABOVE: 16 cats with FCGS, blinded, randomised, placebo-controlled, single veterinary practice, a SINGLE intravenous dose of XENOGENEIC equine peripheral blood-derived MSC versus control, with daily owner evaluations and visits on days -7, 0, 21, 42 and 84. Null on every endpoint: Stomatitis Disease Activity Index showed no significant effect for time (p=0.368), treatment (p=0.626) or interaction (p=0.696); failure time p=0.629; number of animals requiring rescue therapy p=0.26; biopsy analysis over time p=0.386; average owner reports p=0.631. Safety was acceptable - one adverse event and one serious adverse event in each group, neither linked to treatment, with no remarkable haematology or biochemistry changes. Authors verbatim: 'the single intravenous application of ePB-MSCs in cats suffering from FCGS was safe. Based on the current data using the current study design, there was no evidence that the application was more effective than the control.' de Bouvre N, Beerts C, Broeckx SY, Depuydt E, Tack L, Pauwelyn G, Duchateau L, Saunders J, Spaas JH. Front Vet Sci. 2026;13:1857014. PMID 42375508. DOI 10.3389/fvets.2026.1857014. Three design differences could each explain the null - a single dose rather than two, xenogeneic equine rather than feline cells, and n=16 - so it does not prove MSC do not work in FCGS. It is nonetheless the only placebo-controlled evidence that exists in this disease, and it is negative. CELL-FREE / SECRETOME - a case series, not efficacy evidence: 8 cats with refractory FCGS received two to three intramucosal injections of HUMAN-derived MSC secretome three months apart. Only 2/8 had resolution of clinical signs and significant lesion improvement; 6/8 'did not have a substantial clinical response, and lesions remained mostly unchanged'. SDAI decreased in all cats, 6/8 had reduced globulins, 5/8 gained weight, and no adverse effects or clinicopathological abnormalities were attributed to the secretome. The authors themselves call for well-designed clinical trials to verify the observed effects. Almendros A, Nekouei O, Moores C, Jesky R, Baiker K, Tse M. Front Vet Sci. 2025;12:1603383. PMID 40612155. DOI 10.3389/fvets.2025.1603383. This is the closest thing to cell-free evidence in FCGS and it is an 8-cat case series with a 25% response rate - it is not exosome efficacy evidence and must never be presented as such.
What has not been shown
Stated plainly, because each of these gaps is routinely papered over by sellers. (1) NO POSITIVE TRIAL HAS A CONCURRENT CONTROL ARM. Every trial reporting 57-79% response was a pilot case series (Arzi 2016 n=9; Arzi 2017 n=7), an open-label multicentre study (Arzi 2020 n=18), or an industry-sponsored (Gallant) baseline-controlled or open-label field trial (Williams 2025 n=46; Williams 2026 n=35) - none had a concurrent comparison group, so improvement cannot be separated from the natural post-extraction course or from owner expectation. The only randomised, blinded, placebo-controlled trial ever run in FCGS tested a XENOGENEIC EQUINE peripheral blood-derived MSC product as a single intravenous dose and was null on every endpoint; no FELINE-derived MSC product has ever been tested against placebo, so that null neither transfers to the feline products nor vindicates them. In a disease where post-extraction lesions can continue improving on their own for months, absence of a placebo arm is not a technicality. (2) OWNER-REPORTED AND VETERINARIAN-ASSESSED RESULTS DISAGREE BY ABOUT 30 PERCENTAGE POINTS. In the 46-cat trial, day-90 owner-scored success was 75.8-78.8% while veterinarian-assessed lesion healing was 45.5%. Quoting only the owner number is misleading. Note also the shrinking denominators (44 to 38 to 33) - success percentages are computed on completers. (3) NO APPROVED PRODUCT. There is no FDA-approved animal cell, stromal-cell or exosome product for any species, and none authorised by EMA for cats. In the US these are unapproved new animal drugs: FDA CVM has issued warning letters treating cell- and tissue-based veterinary products, including conditioned media, as unapproved new animal drugs. The one EMA-authorised veterinary stem cell medicine relevant to companion animals, DogStem (EMEA/V/C/005829), is an EQUINE umbilical cord-derived MSC product authorised for osteoarthritis in DOGS - it has nothing to do with cats or with gingivostomatitis and must never be cited as though it did. (4) NO EXOSOME OR EXTRACELLULAR-VESICLE PRODUCT HAS IN-VIVO CLINICAL EFFICACY EVIDENCE IN CATS FOR THIS OR ANY INDICATION. The authoritative 2026 review of MSC in veterinary clinical practice states that MSC-derived EV application in veterinary medicine is still very new, with preclinical results far exceeding clinical validation (Zayed M, Jeong BH. Vet J. 2026;320:106837. PMID 42624276. DOI 10.1016/j.tvjl.2026.106837). The 8-cat human-secretome case series above is the whole cell-free FCGS literature and 6 of 8 cats did not respond. (5) NO PEPTIDE HAS ANY FELINE FCGS EVIDENCE. BPC-157, TB-500 (thymosin beta-4), GHK-Cu, KPV and LL-37 have no controlled efficacy evidence in cats, dogs or horses for any indication; a PubMed search for 'BPC 157' combined with cats returned zero records. No peptide in the MicroAmino catalogue has controlled efficacy evidence in any companion-animal species. TB-500 is additionally FEI-banned. Anything sold for feline stomatitis on a peptide rationale is Tier 5, no evidence. (6) NO EVIDENCE THAT CELLS REPLACE OR PRECEDE EXTRACTION. When MSC were given before full-mouth extraction, 3 of 5 cats had no response, 2 had a mild response, and none showed any immune modulation; the investigators state it 'is not recommended at this time' (PMID 33118849). MSC therapy in FCGS is a salvage option for cats that remain refractory AFTER extraction, and nothing else. (7) 'IMMUNE-PRIVILEGED' AND 'IMMUNE-INVISIBLE' ARE NOT DEFENSIBLE CLAIMS. The feline FCGS trials reported no immunogenic safety concerns at one year, which is a safety statement, not evidence of immune invisibility. In dogs, both equine and canine MSC RAISED antibody titres (Punzon E, Garcia-Castillo M, Rico MA, Padilla L, Pradera A. Front Vet Sci. 2023;10:1098029. PMID 37266387. DOI 10.3389/fvets.2023.1098029; randomised controlled trial in 24 police working dogs, intra-articular, in which 'no adverse events were detected... despite both equine and canine MSC generate antibody titres in the dogs') - that study is canine and must be labelled as canine, but it is sufficient to make 'immune-privileged' an unsupportable marketing claim for any species. (8) NO DOSE-RANGING, NO HEAD-TO-HEAD, NO PREDICTIVE TEST IN CLINICAL USE. Every feline trial used 20 million cells IV; no dose-response study exists. There is no trial comparing MSC against ciclosporin or interferon-omega. The CD8lo and CD8-percentage biomarkers and the CASP4 / MMP8 / PTGS2 transcriptomic candidates are research findings, not validated, commercially available patient-selection tests. (9) AUTOLOGOUS CELLS FROM AN AFFECTED CAT MAY BE THE WRONG STARTING MATERIAL. Adipose-MSC exosomes from cats with severe FCGS carried 8 unique proteins, 17 upregulated and 13 downregulated versus healthy controls (Villatoro AJ, Martin-Astorga MDC, Alcoholado C, Cardenas C, Farinas F, Becerra J, Visser R. Animals (Basel). 2021;11(8):2466. PMID 34438923. DOI 10.3390/ani11082466; 5 healthy vs 5 FCGS cats, pooled, with 5 further proteins exclusive to the healthy group and higher exosome output from FCGS-derived cells), i.e. cells harvested from a systemically inflamed cat may be functionally abnormal. Nobody has shown clinically what that means.
Sources
- Arzi 2016 - fresh autologous ASC, 9 enrolled / 7 completed, 5/7 responders — Arzi B, Mills-Ko E, Verstraete FJM, Kol A, Walker NJ, Badgley MR, Fazel N, Murphy WJ, Vapniarsky N, Borjesson DL. Therapeutic efficacy of fresh, autologous mesenchymal stem cells for severe refractory gingivostomatitis in cats. Stem Cells Transl Med. 2016;5(1):75-86. PMID 26582907. DOI 10.5966/sctm.2015-0127 https://doi.org/10.5966/sctm.2015-0127
- Arzi 2017 - fresh allogeneic ASC, 7 cats, 4/7 (57%) responders, remission up to 20 months — Arzi B, Clark KC, Sundaram A, Spriet M, Verstraete FJM, Walker NJ, Loscar MR, Fazel N, Murphy WJ, Vapniarsky N, Borjesson DL. Therapeutic efficacy of fresh, allogeneic mesenchymal stem cells for severe refractory feline chronic gingivostomatitis. Stem Cells Transl Med. 2017;6(8):1710-1722. PMID 28618186. DOI 10.1002/sctm.17-0035 https://doi.org/10.1002/sctm.17-0035
- Arzi 2020 - NIH-funded multicentre shipped ASC, 18 cats, 72% response — Arzi B, Peralta S, Fiani N, Vapniarsky N, Taechangam N, Delatorre U, Clark KC, Walker NJ, Loscar MR, Lommer MJ, Fulton A, Battig J, Borjesson DL. A multicenter experience using adipose-derived mesenchymal stem cell therapy for cats with chronic, non-responsive gingivostomatitis. Stem Cell Res Ther. 2020;11(1):115. PMID 32169089. DOI 10.1186/s13287-020-01623-9 https://doi.org/10.1186/s13287-020-01623-9
- Arzi 2021 - MSC BEFORE full-mouth extraction: negative, not recommended — Arzi B, Taechangam N, Lommer MJ, Walker NJ, Loscar MR, Borjesson DL. Stem cell therapy prior to full-mouth tooth extraction lacks substantial clinical efficacy in cats affected by chronic gingivostomatitis. J Feline Med Surg. 2021;23(6):604-608. PMID 33118849. DOI 10.1177/1098612X20967172 https://doi.org/10.1177/1098612X20967172
- Williams 2025 - pivotal 46-cat allogeneic uterine-derived MSC field study, baseline-controlled, sponsor Gallant — Williams VS, Schneider JL, Parrish RS, Thompson CM, Wrightson C, Taechangam N, Sharif O, Soltero-Rivera M, Arzi B, Black L. Clinical field study evaluating the safety and efficacy of allogeneic uterine-derived mesenchymal stem cells for refractory feline chronic gingivostomatitis. J Feline Med Surg. 2025;27(11). PMID 40999564. DOI 10.1177/1098612X251385852 https://doi.org/10.1177/1098612X251385852
- Williams 2026 - one-year open-label safety extension, 35 cats, no immunogenic or tumorigenic concerns — Williams VS, Schneider JL, Parrish RS, Thompson CM, Wrightson C, Taechangam N, Sharif O, Soltero-Rivera M, Arzi B, Black L. Long-term field safety study evaluating allogeneic, uterine-derived mesenchymal stem cells for refractory feline chronic gingivostomatitis. J Feline Med Surg. 2026;28(4). PMID 41757710. DOI 10.1177/1098612X261431058 https://doi.org/10.1177/1098612X261431058
- de Bouvre 2026 - THE ONLY randomised placebo-controlled trial in FCGS: null on every endpoint — de Bouvre N, Beerts C, Broeckx SY, Depuydt E, Tack L, Pauwelyn G, Duchateau L, Saunders J, Spaas JH. Evaluating the safety and efficacy of equine peripheral blood-derived mesenchymal stem cells in feline chronic gingivostomatitis. Front Vet Sci. 2026;13:1857014. PMID 42375508. DOI 10.3389/fvets.2026.1857014 https://doi.org/10.3389/fvets.2026.1857014
- Almendros 2025 - human MSC secretome, 8 cats, only 2/8 responded (case series) — Almendros A, Nekouei O, Moores C, Jesky R, Baiker K, Tse M. Case report: xenogeneic mesenchymal stem cell secretome for the treatment of feline chronic gingivostomatitis. Front Vet Sci. 2025;12:1603383. PMID 40612155. DOI 10.3389/fvets.2025.1603383 https://doi.org/10.3389/fvets.2025.1603383
- Nekouei 2024 - RCVS Knowledge Summary, 5 interventional studies, evidence graded 'Moderate' with bias caveat — Nekouei O, Wong ST, Leung TKY, Ngai QA, Wong WS, Almendros A. Effectiveness of mesenchymal stem cell therapy in cats with chronic gingivostomatitis. Vet Evid. 2024;9(1). PMID 42005358. DOI 10.18849/ve.v9i1.680 https://doi.org/10.18849/ve.v9i1.680
- Villatoro 2021 - MSC exosomes from FCGS-affected cats are proteomically abnormal, and those cells also produced MORE exosomes (argument against autologous cells here) — Villatoro AJ, Martin-Astorga MDC, Alcoholado C, Cardenas C, Farinas F, Becerra J, Visser R. Altered proteomic profile of adipose tissue-derived mesenchymal stem cell exosomes from cats with severe chronic gingivostomatitis. Animals (Basel). 2021;11(8):2466. PMID 34438923. DOI 10.3390/ani11082466. Exosomes from pooled fAd-MSC of 5 healthy cats vs 5 calicivirus-positive FCGS cats, by UHPLC-HRMS with Gene Ontology enrichment: fAd-MSC from FCGS cats produced MORE exosomes, 8 proteins were exclusive to the FCGS group and 5 exclusive to the healthy group, with 17 proteins significantly upregulated and 13 downregulated in FCGS. n=5 per group, pooled samples, no clinical outcome measured. https://doi.org/10.3390/ani11082466
- Zayed & Jeong 2026 - authoritative review: veterinary MSC-derived EVs are preclinical, not clinically validated — Zayed M, Jeong BH. Mesenchymal stem cells in veterinary clinical practice: evidence from naturally occurring diseases. Vet J. 2026;320:106837. PMID 42624276. DOI 10.1016/j.tvjl.2026.106837 https://doi.org/10.1016/j.tvjl.2026.106837
- Punzon 2023 - CANINE data: both xenogeneic equine and allogeneic canine MSC generated antibody titres in dogs, so 'immune-privileged' is not defensible — Punzon E, Garcia-Castillo M, Rico MA, Padilla L, Pradera A. Local, systemic and immunologic safety comparison between xenogeneic equine umbilical cord mesenchymal stem cells, allogeneic canine adipose mesenchymal stem cells and placebo: a randomized controlled trial. Front Vet Sci. 2023;10:1098029. PMID 37266387. DOI 10.3389/fvets.2023.1098029. Randomised controlled trial, 24 police working dogs 1:1:1, intra-articular, single and repeated administration. Authors verbatim: 'No adverse events were detected following single and repeated MSC administration despite both equine and canine MSC generate antibody titres in the dogs.' THIS IS DOG DATA - it must always be labelled as canine on a feline page. It is cited here for one purpose only: it disproves the marketing claim that MSC are immune-privileged in any species. https://doi.org/10.3389/fvets.2023.1098029
- Winer 2016 - systematic review of FCGS management: data inconsistency prevents direct comparison — Winer JN, Arzi B, Verstraete FJM. Therapeutic management of feline chronic gingivostomatitis: a systematic review of the literature. Front Vet Sci. 2016;3:54. PMID 27486584. DOI 10.3389/fvets.2016.00054 https://doi.org/10.3389/fvets.2016.00054
Tracking response
How you know whether it is working
Stomatitis Disease Activity Index (SDAI) as the primary clinician-scored instrument, supported in the cell-therapy literature by the veterinarian-assessed Global Oral Lesion Score (GOLS) and by Client-Specific Outcome Measures (CSOM) plus an Owner-Reported Assessment of overall response (ORA). Body weight is the third pillar and the least gameable.
SDAI: first published as a 30-point index and used as the primary outcome measure in the only randomised placebo-controlled drug trial in FCGS - Lommer MJ. Efficacy of cyclosporine for chronic, refractory stomatitis in cats: a randomized, placebo-controlled, double-blinded clinical study. J Vet Dent. 2013;30(1):8-17. PMID 23757820. DOI 10.1177/089875641303000101. It is also the primary endpoint of the randomised placebo-controlled MSC trial (de Bouvre et al. Front Vet Sci. 2026;13:1857014. PMID 42375508. DOI 10.3389/fvets.2026.1857014) and of the secretome case series (Almendros et al. Front Vet Sci. 2025;12:1603383. PMID 40612155. DOI 10.3389/fvets.2025.1603383), which makes it the de facto common currency of this disease. HONEST LIMITATION: no separate psychometric validation study for the SDAI was located in this research - it is the consensus instrument by usage, not a formally validated one, and it must not be described as 'validated' without that citation. GOLS, CSOM and ORA are the outcome instruments of the 46-cat and 35-cat uterine-MSC studies (PMID 40999564; PMID 41757710); the roughly 30-percentage-point gap between owner-scored and veterinarian-scored success in those studies is the single most important measurement fact in this disease and any PetSmartMeds follow-up must report both, never only the owner number. The 2016 systematic review specifically called for a consistent semi-quantitative scoring system and longer follow-up because inconsistency between studies made direct comparison unreliable (Winer et al. Front Vet Sci. 2016;3:54. PMID 27486584. DOI 10.3389/fvets.2016.00054).
Suggested cadence: Weight and body condition score at EVERY visit - weight trajectory is the most honest single number in this disease, and in the one-year cell-therapy extension 69% of responders gained weight with a mean increase of 16.2%. Baseline: SDAI, intraoral photographs, weight, pain score, globulins, before any treatment. First recheck 4-6 weeks after extraction: this is the highest-value appointment in the whole course, because resolution of abnormal behaviour (OR 7.2), decrease in oral inflammation (OR 3.5) and lack of need for follow-up antimicrobials (OR 3.7) at the first recheck each predicted a better long-term response in the 95-cat series (PMID 25719848). Recognise that improvement continues for months after extraction on its own - clinical cure or very significant improvement was reached within a median 38 days in one series (PMID 29270412) - so do NOT attribute improvement in the first weeks after surgery to anything added on top of it. On ciclosporin: trough whole-blood concentration measured after 2 weeks and dose adjusted toward >300 ng/mL, because response tracked concentration rather than milligram dose and absorption varied from 32.1 to 1,576.2 ng/mL between cats; re-score SDAI every 2 weeks for the first 6 weeks, which is the interval and duration of the trial evidence. If cell therapy is used, mirror the published schedule exactly so results are comparable: day 14, day 28, day 60 and day 90, then day 180 and day 365, scoring GOLS and CSOM at each. Owner check-in weekly for the first month after any intervention, then monthly once stable. Annual anaesthetised oral reassessment with radiographs for any cat with retained teeth.
Questions you can answer at home
- Is your cat eating on its own? Roughly how much, compared with a normal day before all this started?
- Does your cat still flinch, cry out, or back away from the bowl when it tries to eat?
- Is your cat drooling? Is it less, the same, or more than last time - and is there any pink or blood in it?
- Has your cat started grooming itself again? Does the coat look better, the same, or worse?
- Is your cat pawing at its mouth or rubbing its face on furniture? How many times a day would you guess?
- Is your cat coming to you, sitting with you, or playing more than it was a month ago - or still hiding?
- What does the scale say? Please weigh your cat at home if you can, or tell us if the collar or harness fits differently.
Last reviewed: 2026-09-12 · Every claim on this page carries a citation you can check. If one does not hold up, tell us and we will correct it. science@azzamedical.com
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