Feline stomatitis is a severe, painful inflammation of a cat’s mouth that goes far beyond ordinary gum disease. Formally called feline chronic gingivostomatitis (FCGS), it affects roughly 0.7% to 12% of pet cats, with much higher rates in feral populations. The condition causes deep, ulcerated lesions across the oral tissues, making eating agonizing and often leading to significant weight loss.
What Happens Inside the Mouth
Unlike typical gingivitis, which stays along the gumline, stomatitis spreads across the soft tissues of the mouth. Lesions commonly appear in the back of the mouth near the glossopalatine arch (the tissue where the throat meets the back of the tongue), beneath the tongue, on the lips, and on the roof of the mouth. The tissue around the premolars and molars is especially affected. These aren’t just red, irritated patches. The tissue becomes swollen, ulcerated, and bleeds easily.
Under a microscope, the affected tissue is packed with immune cells, particularly a type called lymphocytes and plasma cells. This dense infiltration signals that the immune system is in a state of chronic overreaction. Cats with stomatitis show elevated levels of inflammatory signaling molecules throughout their bodies, not just in their mouths, suggesting the problem is systemic. Their immune cells are also out of balance: they have a notable increase in certain “effector memory” immune cells that drive ongoing inflammation, while the regulatory cells that normally dial down immune responses aren’t functioning properly.
In short, the disease isn’t caused by infection destroying the tissue directly. It’s the cat’s own immune system attacking the oral mucosa in a sustained, dysregulated way.
What Causes It
No single cause has been identified, which is part of what makes stomatitis so frustrating to treat. The current understanding is that it results from an exaggerated immune response triggered by one or more factors in a genetically susceptible cat. Proposed contributors include viral infections, bacteria from normal oral flora, environmental stress, and nutritional factors.
Feline calicivirus (FCV) has the strongest association. In one study, FCV was detected in the oral tissues of 40.5% of cats with stomatitis compared to 0% of healthy control cats, a statistically significant difference. Other viruses sometimes mentioned, like feline herpesvirus, did not show a meaningful association. Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are also considered potential contributors, though their role appears to be more about suppressing overall immune health than directly triggering the oral inflammation.
The prevailing theory is that in susceptible cats, the presence of certain oral triggers (viral particles, bacteria, even dental plaque) sets off an immune response that the body cannot properly regulate, creating a self-perpetuating cycle of inflammation.
Signs to Recognize
The most obvious sign is extreme oral pain. Cats with stomatitis often approach their food bowl eagerly, then recoil or cry out when they try to eat. Other common signs include:
- Excessive drooling, sometimes tinged with blood
- Severe bad breath
- Weight loss from inability to eat comfortably
- Pawing at the mouth
- Swollen, red, and ulcerated gums that bleed easily
- Unkempt coat, since grooming becomes painful
Some cats stop eating dry food entirely while still managing soft food. Others refuse food altogether during flare-ups. Because compromised nutrition is one of the most serious consequences of stomatitis, weight loss and muscle wasting can become life-threatening if the condition goes untreated.
How It’s Diagnosed
Diagnosis is primarily based on clinical appearance. A veterinarian examining the mouth will see the characteristic pattern of inflammation extending beyond the gums into the deeper oral tissues, particularly in the back of the mouth. Full-mouth dental X-rays are taken under anesthesia to evaluate bone loss around the teeth and check for other dental disease that could be contributing to the inflammation.
If the lesions look unusual or if a mass is present, a tissue biopsy may be recommended to rule out oral cancer. Blood tests for FeLV and FIV are also standard, since these infections affect treatment decisions and overall prognosis. But in most cases, the visual presentation of widespread oral ulceration and inflammation in the characteristic locations is enough to confirm the diagnosis.
Tooth Extraction as Primary Treatment
The most effective treatment for feline stomatitis is extracting the teeth in areas of inflammation, and often all the teeth. This sounds drastic, but the rationale is straightforward: removing the teeth eliminates the surfaces where plaque and bacteria accumulate, which reduces the triggers that perpetuate the immune overreaction.
A study of 95 cats published in the Journal of the American Veterinary Medical Association found that tooth extraction led to complete resolution of stomatitis in 28.4% of cats and substantial improvement in another 39%, meaning roughly two-thirds of cats saw significant benefit. Of those cats that improved, about 69% needed temporary medical support (pain medication, anti-inflammatory drugs) for a period after surgery before reaching their best outcome.
One notable finding: full-mouth extraction did not appear to provide additional benefit over partial extraction (removing only the premolars and molars in affected areas). This means many cats can keep their canine teeth and incisors if those areas are not inflamed.
Recovery from the extraction procedure itself typically takes about a week for cats who have multiple teeth or full-mouth extractions. Cats may be groggy and disoriented immediately after surgery, but most begin eating soft food within a few days. Cats without teeth adapt remarkably well. They eat wet food without difficulty, and many even manage kibble by using their gums and tongue.
When Surgery Isn’t Enough
About one-third of cats continue to have significant oral inflammation even after extraction. For these refractory cases, several medical options exist.
Cyclosporine, an immune-modulating drug given orally, has shown promise. In a randomized, placebo-controlled study of cats whose stomatitis persisted after extraction, about 78% of cats receiving cyclosporine showed more than 40% improvement in their inflammation scores after six weeks, compared to just 14% on placebo. Cats that achieved higher blood levels of the drug did substantially better (72% improvement versus 28%).
Pain medication also plays an important role. Buprenorphine, an opioid pain reliever applied to the inside of the cheek, has been shown to produce reliable pain relief in cats with oral disease and can increase food intake, which is critical for cats that are losing weight. Cats in studies showed increased appetite within 30 to 90 minutes of receiving it. Anti-inflammatory drugs, antibiotics during flare-ups, and corticosteroids are also used as part of symptom management, though long-term steroid use carries its own health risks.
Stem cell therapy is an emerging option for cats that don’t respond to surgery or standard medications. In a multicenter study of 18 cats with refractory stomatitis, intravenous infusions of fat-derived stem cells led to complete cure in about 28% and substantial improvement in another 44%, for an overall positive response rate of 72%. The clinical response took three to six months to develop, and in cats that responded, the improvement appeared to be permanent. This therapy is not yet widely available but is offered at some veterinary specialty centers.
Living With a Cat With Stomatitis
Managing a cat with stomatitis at home centers on two priorities: controlling pain and maintaining nutrition. Soft or puréed food is easier on inflamed mouths, and warming food slightly can make it more appealing. Cats with stomatitis generally refuse dry food entirely, even after treatment.
If your cat is on pain medication or immunosuppressive therapy, regular veterinary check-ups are important to monitor weight, oral inflammation, and any medication side effects. Many cats cycle through better and worse periods, so adjusting treatment over time is normal. The good news is that for the majority of cats, extraction combined with appropriate medical support leads to a significantly better quality of life, even if complete cure isn’t always achievable.