Mouth
Mouth ulcers
Painful sores on the lining of the mouth, lips or tongue that are usually harmless and heal on their own within a couple of weeks, but which occasionally point to an underlying condition or, if long-lasting, need checking to rule out mouth cancer.
Education and reference only. This explains the common causes of mouth ulcers and the warning signs that need urgent help, in plain language — it is not a diagnosis or a substitute for advice from a clinician. If you feel very unwell or are worried, seek medical help.
Quick answer
What is mouth ulcers?
Mouth ulcers are small, painful breaks in the soft lining of the mouth, often round or oval with a pale centre and a red rim. Most are simple aphthous ulcers, triggered by a minor injury such as biting the cheek, a sharp tooth or brace, stress, tiredness or certain foods, and they heal by themselves within one to two weeks.
- Get urgent help: See a doctor or dentist promptly for any mouth ulcer that lasts more than three weeks — a long-lasting sore needs checking to rule out mouth cancer. Seek urgent help for ulcers with a high temperature and feeling very unwell.
- Self-care: Most mouth ulcers heal on their own, and the aim of self-care is to ease the soreness and avoid making them worse.
About mouth ulcers
Mouth ulcers are small, painful breaks in the soft lining of the mouth, often round or oval with a pale centre and a red rim. Most are simple aphthous ulcers, triggered by a minor injury such as biting the cheek, a sharp tooth or brace, stress, tiredness or certain foods, and they heal by themselves within one to two weeks. Some ulcers, though, are part of a wider picture: a yeast infection or a skin condition affecting the mouth, viral cold sores spreading inside the lips, or a sign that the body is short of iron or another nutrient. Recurrent or widespread mouth ulcers can also accompany inflammatory bowel disease. The single most important rule is that any ulcer lasting more than three weeks should be examined, because a persistent sore can occasionally be an early sign of mouth cancer.
When to get help
Call 999 or go to A&E if mouth ulcers comes with any of these warning signs:
- See a doctor or dentist promptly for any mouth ulcer that lasts more than three weeks — a long-lasting sore needs checking to rule out mouth cancer.
- Seek urgent help for ulcers with a high temperature and feeling very unwell.
- Call 999 or seek emergency help for widespread blistering of the mouth, eyes or skin, which can be a severe reaction to a medicine.
- See a doctor if ulcers are so painful that they stop you eating or drinking.
- See a doctor for frequently recurring or unusually large ulcers, as these may have an underlying cause.
When to see a doctor
Most mouth ulcers settle within a couple of weeks and need no more than a pharmacist's advice. Arrange to see a doctor or dentist if an ulcer lasts longer than three weeks, keeps coming back, is unusually large or painful, or is stopping you eating and drinking. Recurrent ulcers alongside tiredness, tummy symptoms or weight loss may point to an underlying condition such as a nutritional deficiency or bowel disease and deserve assessment. Widespread blistering of the mouth, eyes or skin needs urgent attention.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
What can cause it
Common causes of mouth ulcers
Mouth ulcers has many possible causes. Each links to a full, plain-language guide to that condition — what it is, how it's treated and when to seek help.
What helps
Self-care and what you can do
Most mouth ulcers heal on their own, and the aim of self-care is to ease the soreness and avoid making them worse. Eat soft, cool foods and avoid anything spicy, acidic, salty or sharp that stings the ulcer, and use a straw for drinks if it helps keep them away from the sore. Keep the mouth clean with gentle brushing using a soft toothbrush, and a pharmacist can recommend a soothing mouthwash, gel or protective paste for the ulcer. Try to identify and avoid triggers such as a sharp tooth edge, stress or tiredness. Drinking plenty of fluids and not smoking both help the lining of the mouth heal.
Answers
Mouth ulcers: frequently asked questions
How long do mouth ulcers usually last?
Most simple mouth ulcers heal on their own within one to two weeks. Any ulcer that lasts longer than three weeks should be checked by a doctor or dentist, because a persistent sore in the mouth occasionally signals something more serious.
What causes recurrent mouth ulcers?
Common causes include minor injury from a sharp tooth or brace, stress, tiredness and certain foods. Recurrent ulcers can also reflect a shortage of iron or other nutrients, or an underlying condition such as inflammatory bowel disease, which is worth investigating.
When should I worry about a mouth ulcer?
See a doctor or dentist if an ulcer lasts more than three weeks, is unusually large, or keeps recurring. Widespread blistering of the mouth, eyes or skin, or ulcers with a high fever and feeling very unwell, need urgent assessment.
How can I soothe a painful mouth ulcer?
Avoid spicy, acidic, salty or sharp foods, eat soft cool foods, and keep your mouth clean with a soft toothbrush. A pharmacist can suggest a soothing mouthwash, gel or protective paste to ease the pain while the ulcer heals.
Sources
Where this is drawn from
- NICE CKS: Aphthous ulcer.
- Oral Health Foundation: mouth ulcers information.
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