Skip to main content
Pet A&E
Animal Trust Logo
Book or Register
Animal Trust

Symptom: Sore Mouth – Why does my pet have a sore mouth?

A sore mouth can be caused by problems affecting the teeth, gums, tongue or other tissues inside the mouth. Pets may not always show obvious signs of mouth pain, so changes in eating habits or behaviour can be important clues. 

Signs of a sore mouth can include: 

  • Red, swollen or bleeding gums 

  • Ulcers, sores or unusual lumps in the mouth 

  • Drooling, sometimes with blood in the saliva 

  • Dropping food or eating more slowly than usual 

  • Difficulty chewing or swallowing 

  • Chewing on one side of the mouth 

  • Pawing or rubbing at the mouth or face 

  • Pulling away or resisting when the mouth or face is touched 

  • Becoming quieter, withdrawn or more irritable than usual 

Symptom: Sore Mouth – Why does my pet have a sore mouth?

'My pet has bad breath' - Frequently asked questions

There are several possible causes of a sore mouth in dogs and cats, including: 

  • Dental disease – inflammation or infection affecting the teeth and gums can cause significant pain. 

  • Broken or damaged teeth – a fractured or damaged tooth can expose sensitive tissues and cause pain. 

  • Mouth injuries or foreign objects – cuts or other injuries inside the mouth, including those caused by something stuck in the mouth, can cause soreness. 

  • Mouth ulcers or inflammation – sores or inflammation can affect the gums, tongue, cheeks or other tissues inside the mouth. Some illnesses can also cause mouth ulcers or inflammation. 

  • Oral masses – lumps or abnormal tissue in the mouth can cause discomfort and should be assessed by a vet. 

Further reading: Dental Disease in Dogs, Dental Disease in Cats

If you think your pet has a sore mouth, contact your vet for advice and arrange an examination. Mouth pain can have many different causes, and some conditions require prompt treatment. 

While you are waiting to see your vet, make sure your pet has access to fresh water and, if they are willing to eat, you can offer soft food if this is more comfortable for them. 

Do not try to examine or clean your pet’s mouth if this appears to be painful, as this may cause further discomfort or injury. 

  • Do not give human painkillers or other human medicines unless specifically advised by your vet. 

  • Do not force your pet’s mouth open or try to remove something that is stuck. 

  • Do not use human oral hygiene products or unapproved home remedies in your pet’s mouth. 

  • Do not delay contacting your vet, particularly if your pet is not eating, appears painful or has swelling or bleeding. 

Contact your vet if you notice signs that your pet may have a sore mouth, particularly if the signs persist or are getting worse. 

Seek urgent veterinary care if your pet: 

  • Has significant or ongoing bleeding from the mouth 

  • Is unable to open or close their mouth normally 

  • Is unable or unwilling to eat or drink 

  • Appears to be in significant pain 

Author

Written by Gillian Burkhill, Veterinary Surgeon, Animal Trust Vets CIC | Published September 2026 | Review date September 2029 | This advice is for UK pets only and is not a replacement for seeing a vet

Concerned about your pet?