Stomatitis itself is not contagious between cats. It is an immune-mediated condition, meaning a cat’s own overactive immune system drives the severe oral inflammation. You cannot “catch” stomatitis the way you catch a cold. However, some of the underlying infections linked to stomatitis, particularly feline calicivirus, are highly contagious, and that distinction matters if you have multiple cats.
Why Stomatitis Isn’t Directly Contagious
Feline chronic gingivostomatitis (FCGS) develops when a cat’s immune system mounts an excessive, unresolved inflammatory response to bacteria and viruses in the mouth. The oral tissue of affected cats shows a pattern of immune cell activation that healthy cats simply don’t have, even when exposed to the same germs. Researchers have tried to recreate chronic stomatitis by infecting healthy cats with calicivirus. The cats developed short-term mouth inflammation, but none went on to develop the chronic disease. This confirms that the virus alone isn’t enough. Something about the individual cat’s immune response determines whether stomatitis takes hold.
The cause remains officially unknown. What researchers do know is that it involves a combination of oral bacteria imbalance, viral triggers, and an immune system that can’t resolve the resulting inflammation. Think of it less like an infection and more like an allergic-type overreaction happening inside the mouth.
The Calicivirus Connection
About 60% of cats with stomatitis test positive for feline calicivirus (FCV), compared to roughly 24% of healthy cats. FCV is a core part of the picture for most stomatitis cases, and it is extremely contagious between cats through saliva, nasal secretions, and shared food bowls.
Here’s the important nuance: FCV spreads easily, but stomatitis does not. Most cats exposed to calicivirus will either fight it off, develop mild upper respiratory symptoms, or become carriers without ever developing mouth inflammation. Only a small subset of cats, those with a particular immune vulnerability, go on to develop chronic stomatitis. So while your cat with stomatitis can pass calicivirus to your other cats, it is very unlikely to give them stomatitis specifically.
All cats should be vaccinated against FCV as part of their core vaccine schedule. Vaccination typically protects against severe disease but does not completely prevent infection or viral shedding.
Multi-Cat Households Raise the Risk
Even though stomatitis isn’t contagious in the traditional sense, living with other cats is one of the strongest risk factors for developing it. Cats in multi-cat households have roughly seven times the odds of developing stomatitis compared to cats living alone. Each additional cat in the home increases the odds by more than 70%. Cats with outdoor access, or those living with other cats that go outdoors, also face higher risk.
The likely explanation is viral exposure load. In homes with multiple cats, viruses like calicivirus circulate more freely and repeatedly. A cat whose immune system is already predisposed to overreact faces constant re-exposure, which may be the trigger that tips the balance from normal immune function to chronic inflammation. This doesn’t mean you need to rehome your cats, but it’s worth understanding that the shared environment plays a role even though the disease itself isn’t passed from cat to cat.
Retroviruses and Immune Suppression
Cats with stomatitis are far more likely to test positive for feline immunodeficiency virus (FIV) or feline leukemia virus (FeLV) than orally healthy cats. Around 12% of cats with stomatitis test positive for FIV, compared to just 1.3% of cats with healthy mouths. For FeLV, the rate is about 10% in stomatitis cats versus 2.2% in healthy ones. Cats with stomatitis are roughly five times more likely to be FeLV-positive than orally healthy cats.
Both FIV and FeLV suppress the immune system, which may make affected cats more vulnerable to the kind of dysregulated immune response that drives stomatitis. Both viruses are also contagious between cats: FIV primarily through bite wounds, and FeLV through prolonged close contact and shared bowls. If your cat with stomatitis hasn’t been tested for these viruses, that’s a worthwhile conversation with your vet, both for managing the stomatitis and for understanding the risk to other cats in the home.
What Stomatitis Looks Like
Stomatitis goes well beyond ordinary gum disease. Regular gingivitis involves redness along the gum line. Stomatitis extends past the gums into the deeper tissues of the mouth, including the back of the throat (called caudal stomatitis), the inner cheeks, and sometimes the tissue around the tongue. The inflammation is often bright red, raw-looking, and visibly painful.
Cats with stomatitis commonly drool excessively, drop food while eating, paw at their mouths, lose weight, and develop bad breath. Some stop eating entirely because of the pain. The condition is chronic, meaning it doesn’t resolve on its own and tends to persist or worsen without treatment.
How Stomatitis Is Treated
The most effective treatment is extraction of most or all teeth. This sounds drastic, but removing the teeth eliminates the surfaces where plaque bacteria accumulate, which reduces the constant immune trigger. About 80% of cats show significant improvement or complete remission after full or near-full mouth extractions. Most cats eat comfortably without teeth, including dry food, because cats don’t chew the way humans do.
For the roughly 20% of cats that don’t fully respond to extractions, additional options exist. Stem cell therapy has shown promise as a newer treatment for these refractory cases. In long-term studies, about 59% of cats treated with stem cells experienced permanent improvement or cure, with an overall positive response rate of around 66%. The treatment involves intravenous infusions given about a month apart. It’s not yet widely available at every veterinary practice, but it’s increasingly accessible at specialty clinics.
Some cats are managed with ongoing anti-inflammatory or immune-modulating medications, particularly those whose owners prefer to delay extractions or whose cases are mild enough to control medically. These approaches typically manage symptoms rather than resolve the underlying problem.
Practical Steps for Multi-Cat Homes
If one of your cats has stomatitis, you don’t need to isolate them from your other cats to prevent stomatitis from “spreading.” The disease itself cannot be transmitted. What you can do is reduce viral circulation in the household by keeping food and water bowls separate, maintaining good litter box hygiene, and ensuring all cats are up to date on core vaccinations including calicivirus.
Testing all household cats for FIV and FeLV is reasonable, especially if the affected cat tests positive for either virus. Reducing overall stress in the home, providing enough resources so cats don’t compete for food, water, or resting spots, can also support healthier immune function across the board. Cats that develop signs of mouth pain, drooling, or reluctance to eat should be examined promptly, since early intervention tends to produce better outcomes.