Cat Mouth Sores

Mouth sores in cats can be very painful and may point to dental disease, viral infection, inflammation, or other serious problems. Because cats often hide illness and pain, any visible sore, drooling, or trouble eating deserves prompt attention.

When to Call a Vet for Mouth Sores in Cats

Emergency

Go to the ER now

  • Your cat is struggling to breathe, open-mouth breathing, or has severe swelling of the face, mouth, or throat.
  • Your cat cannot eat or drink, seems unable to swallow, or is becoming weak or dehydrated.
  • There is heavy bleeding from the mouth, severe trauma, or concern your cat chewed a chemical, caustic substance, electrical cord, or toxic plant.
  • Your cat is suddenly collapsing, extremely lethargic, or has a rapidly worsening illness along with mouth ulcers.
  • You see a large mass, severe tissue destruction, or intense pain that makes your cat cry out when trying to eat or yawn.
Urgent

See a vet within 24 hours

  • You notice any mouth sores, ulcers, red inflamed gums, or bad breath lasting more than 24 hours.
  • Your cat is drooling, pawing at the mouth, dropping food, chewing on one side, or showing 'approach but won’t eat' behavior.
  • Your cat seems painful when opening the mouth, resists having the face touched, or stops grooming normally.
  • Your cat has reduced appetite, weight loss, fever, or swollen lymph nodes along with mouth lesions.
  • Your cat is a kitten, senior, or has known kidney disease, calicivirus, FeLV, FIV, or a history of dental disease.
Monitor

Watch at home, call if it worsens

  • A very small sore may be monitored briefly only if your cat is otherwise acting normal, eating well, drinking well, and the area does not worsen.
  • Keep a close eye on appetite, drooling, grooming, breath odor, and whether your cat seems painful when eating.
  • If the sore is still present after 24 hours, new sores appear, or your cat seems uncomfortable, call your vet.
  • Do not use human mouth rinses, gels, or pain medicines unless your veterinarian specifically recommends them.
  • If you are unsure what caused the sore, it is safest to call your vet for guidance.

Common Causes of Cat Mouth Sores

🦷

Dental disease and tooth resorption

Dental disease is common in cats and can cause marked oral pain, inflamed gums, drooling, and ulcer-like lesions. Tooth resorption and periodontal disease are especially important causes of mouth discomfort.

🔥

Feline stomatitis

Stomatitis is a severe, painful inflammatory disease that can affect the gums, cheeks, and tissues at the back of the mouth. Cats may have bad breath, blood-tinged saliva, trouble eating, and progressive weight loss.

🦠

Viral infections

Feline calicivirus commonly causes painful ulcers on the tongue, gums, lips, or palate. Other viral diseases, including FeLV and FIV, may also contribute to oral inflammation or make a cat more vulnerable to severe disease.

🫘

Kidney disease and other internal illness

Systemic illness can sometimes lead to oral ulceration, especially in cats with uremia from kidney disease. Mouth sores paired with poor appetite, vomiting, or lethargy should be checked promptly.

🌿

Foreign material, burns, or chemical irritation

Chewing irritating plants, caustic substances, or foreign material can injure the lining of the mouth. Burns and toxin exposures can damage more than just the mouth, so these cases need fast veterinary care.

🎗️

Oral tumors or eosinophilic ulcers

Some mouth lesions are caused by cancer or inflammatory conditions such as eosinophilic granuloma complex. A sore that does not heal, bleeds easily, or forms a lump should always be evaluated by a veterinarian.

What to Do at Home

Mouth sores are often painful, and cats may hide that pain until the problem is advanced. Home care should focus on keeping your cat comfortable and getting veterinary help rather than trying to treat the sore yourself. Many causes of oral ulcers, including stomatitis, dental disease, calicivirus, kidney disease, and oral tumors, need a hands-on exam and sometimes sedation, dental imaging, bloodwork, or biopsy for diagnosis.

  • Offer soft, easy-to-eat food and fresh water. If your cat refuses food, call your vet promptly because cats should not go long without eating.
  • Watch for drooling, blood-tinged saliva, bad breath, pawing at the mouth, chattering, food dropping, or weight loss, and note when these signs started.
  • Do not give human pain relievers, numbing gels, peroxide, or mouthwash, as many are unsafe for cats.
  • Do not force your cat’s mouth open if it seems painful or if there is a risk of being bitten.
  • If you suspect exposure to a toxin, chemical, electrical cord, or irritating plant, contact your veterinarian right away.
  • If your cat has recurring mouth sores, reduced appetite, or any visible lesion that does not quickly resolve, schedule a veterinary exam.
🏠

Frequently Asked Questions

Why does my cat have sores in its mouth?
Common causes include dental disease, tooth resorption, feline stomatitis, viral infections such as calicivirus, systemic illness like kidney disease, oral injury, and sometimes tumors or eosinophilic ulcers. Because several of these conditions are painful and can worsen over time, your cat should be examined by a veterinarian.
Are mouth sores in cats an emergency?
They can be. Mouth sores are an emergency if your cat is having trouble breathing, cannot swallow, will not eat or drink, is bleeding heavily, has facial swelling, or may have chewed something toxic or caustic. Even when not an emergency, mouth sores are usually an urgent reason to call your vet because cats often hide significant pain.
Can feline calicivirus cause mouth ulcers?
Yes. Feline calicivirus is a well-recognized cause of painful oral ulcers, especially on the tongue, gums, lips, or hard palate. Cats may also drool, have bad breath, act lethargic, and show upper respiratory signs such as sneezing or nasal discharge.
What does stomatitis look like in cats?
Stomatitis often causes intense redness and inflammation in the mouth, especially around the gums and at the back of the mouth. Cats may drool, have foul breath, cry out when yawning or trying to eat, avoid food despite seeming hungry, and lose weight over time.
What can I safely do for my cat at home?
Offer soft food, keep fresh water available, and minimize stress until your cat can be seen. Do not use human oral products or pain medicines, and do not try to scrape or treat the lesion yourself. If your cat seems painful, stops eating, or the sore is not improving quickly, call your vet.

Disclaimer: The information provided in this article is for educational purposes only and does not constitute veterinary medical advice. Reading this content does not establish a veterinarian-client-patient relationship. Every pet is different — always consult a licensed veterinarian before making decisions about your pet's health, diet, or care. If you'd like personalized guidance, you can talk to one of our vets. If your pet is experiencing a medical emergency, contact your local emergency animal hospital immediately.

Still worried about your cat?

Get personalized advice from a licensed veterinarian.