# Stomatitis in Dogs and Cats: Causes and Care Stomatitis in dogs and cats means inflammation of the soft tissues inside the mouth, and it is a sign of an underlying problem instead of a single disease. Cats most often develop a severe immune-driven form tied to chronic gingivostomatitis, while dogs more commonly have contact lesions from periodontal disease or a distinct ulcerative condition. Both species feel real pain, and both need a veterinarian to sort out the cause before treatment can work. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - Stomatitis is inflammation of the gums, lips, tongue, cheeks, or back of the mouth, and it is always a symptom, not a final diagnosis. - Cats with chronic gingivostomatitis often have severe pain, drooling, and trouble eating, and many need tooth extraction plus medical therapy. - Dogs with lymphoplasmacytic stomatitis often have contact lesions from periodontal disease, and only a minority need full-mouth extractions [1]. - Diagnosis starts with a full oral exam under sedation or anesthesia, plus blood work and testing for viruses or other triggers. - Never give human pain relievers or antibiotics to a pet with a sore mouth. Some are toxic, and the dose must be calculated by your veterinarian. ## What Is Stomatitis in Dogs and Cats? Stomatitis is the medical term for inflammation of the oral mucosa, the moist lining inside the mouth. It can affect the gums, inner lips, tongue, floor of the mouth, and the back of the throat. The inflammation may be mild and patchy or severe and widespread. In cats, the most common and most serious form is called feline chronic gingivostomatitis (FCGS). It is a persistent, painful inflammation that does not resolve on its own and often worsens over time [2]. It is sometimes called refractory stomatitis because it resists simple treatment [2]. In dogs, the picture is different. Lymphoplasmacytic oral mucosal inflammation is common and often nonspecific, meaning the same appearance can come from several causes [1]. A frequent pattern is contact lesions, where the inflamed area sits right next to a diseased tooth or a pocket of periodontal infection [1]. A smaller group of dogs has canine chronic ulcerative stomatitis (CCUS), which is more widespread and harder to manage [1]. The practical point for owners is this: a red, angry mouth in a dog and a red, angry mouth in a cat usually mean different things, and they are treated differently. Assuming a dog should be handled like a cat with FCGS can lead to the wrong care [1]. ## Signs Owners Notice at Home Mouth pain in pets is easy to miss because animals hide it well. Watch for changes in eating and behavior instead of a dramatic cry of pain. Common signs include: - Bad breath that is worse than usual - Drooling, sometimes with blood-tinged saliva - Dropping food, chewing on one side, or refusing hard kibble - Crying out or pulling away when the muzzle or mouth is touched - Pawing at the face or rubbing the mouth - Weight loss and reduced grooming - Lethargy and a dull coat from not eating well In cats with FCGS, drooling and reduced grooming are especially common, and these signs improve measurably when the condition is treated [2]. Cats with gingivostomatitis also tend to have lower vitamin D levels than healthy cats, which may reflect how sick and how poorly eating they have been [3]. Dogs with contact lesions often have obvious dental disease, including heavy tartar, red gums, and loose teeth. If your pet has not had a dental exam in a while, see [Dental Disease In Dogs And Cats](/knowledge/veterinary-medicine/dental-care/dental-disease-in-dogs-and-cats) for what to expect. ## Causes and Risk Factors Stomatitis has many triggers, and often more than one is involved. ### In Cats Feline chronic gingivostomatitis is believed to be immune-mediated, meaning the body's own defenses attack the mouth tissues. Viral infections are strongly linked. In one study of cats with feline infectious peritonitis, feline calicivirus infection was significantly associated with FCGS, while other viruses tested (feline foamy virus, feline herpesvirus, feline immunodeficiency virus, feline leukemia virus, and feline gammaherpesvirus) did not show a significant link [4]. That does not mean those other viruses are harmless, only that calicivirus stood out in that group [4]. Other factors that appear in cats with gingivostomatitis include low serum vitamin D, which was significantly lower in affected cats than in healthy cats in one small study [3]. Whether low vitamin D causes the disease or results from it is not settled, and the authors called for larger studies before recommending supplementation [3]. ### In Dogs In dogs, the most common driver is periodontal disease. Bacteria and tartar around the teeth create constant irritation, and the inflamed tissue forms contact lesions right where the diseased tooth touches the cheek or lip [1]. This is why a thorough dental evaluation matters so much in dogs with a sore mouth. Canine chronic ulcerative stomatitis is a separate, more widespread immune-related condition. It is less common than contact lesions and typically needs more aggressive treatment [1]. ### Shared Triggers in Both Species Other causes of oral inflammation apply to dogs and cats alike: - Oral trauma, such as chewing on sharp bones, sticks, or foreign objects - Chemical or caustic irritants - Foreign material embedded in the tissue, such as grass awns or plant material - Infections, including some parasites and systemic diseases - Kidney disease, liver disease, and other metabolic problems that cause oral ulcers In large animals, traumatic injury from grass awns and similar plant material is a well-recognized cause of stomatitis, and removing the animal from the source often allows recovery [5]. The same principle of removing the irritant applies to pets, though the specific plants and risks differ. If your pet has been vomiting or has other systemic signs along with mouth pain, conditions like pancreatitis can also cause lethargy and appetite loss, so see [Causes Of Pancreatitis In Dogs And Cats](/knowledge/veterinary-medicine/clinical-methods/causes-of-pancreatitis-in-dogs-and-cats) for comparison. ## How Stomatitis Is Diagnosed Diagnosis is a process, not a single test. Your veterinarian will work through several steps. ### Step 1: History and Physical Exam Your vet will ask about eating, drooling, weight change, and how long signs have been present. They will look at the outside of the face and try to examine the mouth, though pain often limits how much can be seen while the pet is awake. ### Step 2: Oral Examination Under Sedation or Anesthesia A complete look at the mouth usually requires sedation or general anesthesia. This allows the vet to inspect the back of the throat, the tongue, the gums, and every tooth, and to check for embedded foreign material [5]. Probing around each tooth checks for pockets and loose teeth. ### Step 3: Dental Radiographs X-rays of the mouth show what the eye cannot: root disease, bone loss, and retained roots. In dogs, radiographic findings help distinguish contact lesions from CCUS, which changes the treatment plan [1]. ### Step 4: Blood Work and Infectious Disease Testing Blood work checks for anemia, organ problems, and signs of systemic inflammation. In cats, testing for feline calicivirus and other viruses is reasonable, since calicivirus is associated with FCGS [4]. Your vet may also check vitamin D levels, though this is not yet a standard test for every case [3]. ### Step 5: Biopsy A tissue sample confirms the type of inflammation and rules out tumors or other serious disease. This is especially useful in dogs, where the same appearance can have several causes [1]. | Test or Step | What It Looks For | Why It Matters | |---|---|---| | Oral exam under anesthesia | Ulcers, foreign material, tooth disease | Finds the visible cause and guides the plan [5] | | Dental radiographs | Root and bone disease | Separates contact lesions from widespread disease in dogs [1] | | Blood work | Anemia, organ disease, inflammation | Rules out systemic causes and checks safety for treatment | | Viral testing (cats) | Calicivirus and other viruses | Calicivirus is linked to FCGS [4] | | Biopsy | Type of inflammation, cancer | Confirms diagnosis when the cause is unclear [1] | ## Treatment Options Treatment depends on the species, the cause, and how severe the disease is. ### Cats With Chronic Gingivostomatitis Tooth extraction has long been the primary surgical treatment for cats with FCGS, but the cure rate is not high enough on its own [2]. Many cats improve after extraction, and some need ongoing medical therapy. Medical management is an active area of research. In one study, a combination of an antibacterial agent and an antiviral agent was given orally to cats with FCGS, including cats that had already had teeth extracted and cats that had not [2]. All measured physical signs improved significantly, including weight, appetite, activity level, grooming, drooling, and redness of the gums [2]. This is promising, but it does not replace a full diagnostic workup, and your veterinarian will decide whether such therapy fits your cat. Pain control and anti-inflammatory medication are central to comfort. Your vet calculates every dose from your cat's weight, kidney and liver values, and other medications. Never use human pain relievers, since several are highly toxic to cats. ### Dogs With Stomatitis For dogs with contact lesions, treating the periodontal disease is the priority. That usually means a professional dental cleaning with radiographs, and extraction of teeth that cannot be saved. The hypothesis in one review of 42 dogs was that only a minority would need full-mouth extractions, and the authors emphasized that treating dogs like cats with FCGS can lead to inappropriate care [1]. Dogs with CCUS often need more than dental work. Immune-suppressing medication, pain control, and sometimes specialized diets are used. Your veterinarian will tailor the plan to your dog's biopsy results and response to treatment. ### Supportive Care for Both Species - Soft, palatable food while the mouth heals - Pain medication prescribed by your vet - Antibiotics only when a bacterial infection is confirmed or strongly suspected - Treatment of any underlying kidney, liver, or viral disease - Good home dental care once the mouth is comfortable If your pet also has vomiting, diarrhea, or weight loss, parasites and other gut problems can overlap with mouth disease. See [Intestinal Parasites in Dogs and Cats: Signs and Prevention](/knowledge/veterinary-medicine/parasitic-diseases/intestinal-parasites-in-dogs-and-cats) for more on that topic. ## Recovery, Outlook, and Long-Term Management Recovery varies widely. Some cats improve dramatically after extractions, while others need months of medical management and may never be fully cured [2]. Dogs with contact lesions often do very well once the diseased teeth are removed, because the source of irritation is gone [1]. Dogs with CCUS tend to need longer, more involved care [1]. Expect several recheck visits. Your vet will look at weight, appetite, and the mouth itself to judge progress. In cats, improvements in drooling, grooming, and gum redness are meaningful signs that treatment is working [2]. Long-term management usually includes: - Regular professional dental cleanings - Daily brushing at home if your pet tolerates it - Monitoring weight and appetite at home - Prompt attention to any return of drooling or mouth pain - Ongoing medication for immune-related disease when needed Vitamin D status may matter in cats with gingivostomatitis, but supplementation is not yet proven to help, and the researchers who found the deficiency called for more study before recommending it [3]. ## Prevention You cannot prevent every case of stomatitis, but you can lower the risk. - Brush your pet's teeth or use vet-approved dental products daily. - Schedule regular veterinary dental exams and cleanings. - Avoid bones, antlers, and hard chews that can fracture teeth or cut the mouth. - Keep your pet away from caustic chemicals, including household cleaners and lawn treatments. - Keep vaccinations current, especially for cats, since calicivirus is linked to FCGS [4]. - Check the mouth at home monthly. Lift the lip and look at the gums and teeth. - Address dental disease early, before contact lesions form [1]. ## Limitations and When to Contact a Veterinarian This article covers general information only. Your pet's individual case needs a veterinarian who can examine the mouth, run tests, and set a treatment plan. Contact your veterinarian the same day if your pet: - Stops eating or drinking for more than 24 hours - Drools heavily or drools blood - Cries when the mouth is touched - Has visible ulcers, swelling, or a foul odor from the mouth - Has lost weight or is losing condition Go to an emergency clinic now if your pet: - Cannot swallow or is choking - Has trouble breathing - Has heavy bleeding from the mouth - Collapses or seems severely weak Call a routine visit if your pet: - Has bad breath that keeps getting worse - Chews on one side or drops food - Has tartar, red gums, or loose teeth - Has been diagnosed with stomatitis before and signs are returning If you suspect your pet ate something toxic, call the ASPCA Animal Poison Control Center at (888) 426-4435 or the Pet Poison Helpline at (855) 764-7661. These lines may charge a consultation fee. ## Frequently Asked Questions ### Is stomatitis contagious to other pets? It depends on the cause. The inflammation itself is not contagious, but some underlying triggers, such as feline calicivirus, can spread between cats [4]. Keep a cat with active mouth disease separated from other cats until your veterinarian advises otherwise. ### Will my pet need all of its teeth removed? Not necessarily. In dogs, the thinking has shifted, and only a minority of dogs with lymphoplasmacytic stomatitis appear to need full-mouth extractions [1]. In cats, extraction is still the main surgical option, but it does not cure every case [2]. ### Can stomatitis be cured with antibiotics alone? No. Antibiotics target bacteria, and most stomatitis in cats and many cases in dogs are driven by immune or viral factors, not bacteria alone [1][2]. Antibiotics may be part of the plan, but they are rarely the whole answer. ### Is there a special diet for pets with stomatitis? Soft, moist food is often easier to eat while the mouth is sore. Your veterinarian may recommend a specific diet based on your pet's other health conditions, so ask before making a big change. ### How long does recovery take after treatment? It varies. Some pets improve within days of dental treatment, while others need weeks to months of medical management [1][2]. Your veterinarian will set recheck intervals based on how your pet responds. ## Related Articles - [Causes Of Pancreatitis In Dogs And Cats](/knowledge/veterinary-medicine/clinical-methods/causes-of-pancreatitis-in-dogs-and-cats) - [Intestinal Parasites in Dogs and Cats: Signs and Prevention](/knowledge/veterinary-medicine/parasitic-diseases/intestinal-parasites-in-dogs-and-cats) - [Dental Disease In Dogs And Cats](/knowledge/veterinary-medicine/dental-care/dental-disease-in-dogs-and-cats) - [Pancreatitis In Cats Symptoms](/knowledge/veterinary-medicine/symptom-guides/pancreatitis-in-cats-symptoms) - [Pancreatitis in Dogs: Symptoms and Care](/knowledge/veterinary-medicine/clinical-methods/pancreatitis-in-dogs-symptoms-and-care) - [What Can Cause A Urinary Tract Infection In A Cat](/knowledge/veterinary-medicine/clinical-methods/what-can-cause-a-urinary-tract-infection-in-a-cat) - [Chronic Stomatitis in Dogs: Causes and Treatment](/knowledge/veterinary-medicine/dental-care/chronic-stomatitis-in-dogs) - [Stomatitis in Dogs: Mouth Symptoms and Causes](/knowledge/veterinary-medicine/dental-care/stomatitis-dogs-symptoms-causes) - [Stomatitis in Dogs: Treatment Options That Work](/knowledge/veterinary-medicine/dental-care/stomatitis-dogs-treatment) ## References 1. [Surgical outcomes in canine lymphoplasmacytic stomatitis: a retrospective study of 42 dogs (2012-2022)](https://pubmed.ncbi.nlm.nih.gov/41445593/). Frontiers in veterinary science, 2025. 2. [Combination Therapeutic Effect of Antibacterial and Antiviral Agents on Feline Chronic Gingivostomatitis Nonbounded to Prior Tooth Extraction Confirmed by Physical Signs and Clinical Biomarkers](https://pubmed.ncbi.nlm.nih.gov/42076735/). Veterinary sciences, 2026. 3. [Evaluation of Serum Vitamin D and C Concentrations in Cats With Gingivostomatitis](https://pubmed.ncbi.nlm.nih.gov/40173273/). Veterinary medicine and science, 2025. 4. [Viral Coinfections Potentially Associated with Feline Chronic Gingivostomatitis in Cats with Feline Infectious Peritonitis](https://pubmed.ncbi.nlm.nih.gov/41305526/). Viruses, 2025. 5. [Stomatitis in Large Animals - Digestive System](https://www.merckvetmanual.com/digestive-system/diseases-of-the-mouth-in-large-animals/stomatitis-in-large-animals). Merck Veterinary Manual. ## Further Reading - [Papular Stomatitis in Large Animals - Digestive System (Merck Veterinary Manual)](https://www.merckvetmanual.com/digestive-system/diseases-of-the-mouth-in-large-animals/papular-stomatitis-in-large-animals) - [Merck Veterinary Manual: Dog Owners](https://www.merckvetmanual.com/dog-owners) - [Merck Veterinary Manual: Cat Owners](https://www.merckvetmanual.com/cat-owners)