Learn more about mouth ulcer: overview

Mouth ulcers are common and should clear up on their own within a week or 2. They're rarely a sign of anything serious, but may be uncomfortable to live with.

Mouth ulcers need time to heal and there's no quick fix.

Avoiding things that irritate your mouth ulcer should help:

  • speed up the healing process
  • reduce pain
  • reduce the chance of it returning

Do

  • use a soft-bristled toothbrush
  • drink cool drinks through a straw
  • eat softer foods
  • get regular dental check-ups
  • eat a healthy, balanced diet

Don't

  • do not eat very spicy, salty or acidic food
  • do not eat rough, crunchy food, such as toast or crisps
  • do not drink very hot or acidic drinks, such as fruit juice
  • do not use chewing gum
  • do not use toothpaste containing sodium lauryl sulphate

A pharmacist can help with mouth ulcers

A pharmacist can recommend a treatment to speed up healing, prevent infection or reduce pain, such as:

  • antimicrobial mouthwash
  • a painkilling mouthwash, gel or spray
  • corticosteroid lozenges

You can buy these without a prescription, but they may not always work.

Find a pharmacy

See a dentist or GP if your mouth ulcer:

  • lasts longer than 3 weeks
  • keeps coming back
  • becomes more painful and red – this may be a sign of an infection

Although most mouth ulcers are harmless, a long-lasting mouth ulcer is sometimes a sign of mouth cancer. It's best to get it checked.

Your GP or dentist may prescribe stronger medication to treat severe, recurrent or infected mouth ulcers.

Single mouth ulcer on the inside of the bottom lip
Mouth ulcers usually appear inside the mouth, on the cheeks or lips.
Clear white-coloured mouth ulcer on the tip of the tongue
Ulcers can also appear on the tongue.

You may have more than 1 ulcer at a time and they can change in size.

Mouth ulcers are not contagious and should not be confused with cold sores.

Cold sores appear on the lips or around the mouth and often begin with a tingling, itching or burning sensation.

If you have several mouth ulcers, this can be a symptom of:

You cannot always prevent mouth ulcers

Most single mouth ulcers are caused by things you can try to avoid, such as:

  • biting the inside of your cheek
  • badly fitting dentures, braces, rough fillings or a sharp tooth
  • cuts or burns while eating or drinking – for example, hard food or hot drinks
  • a food intolerance or allergy
  • damaging your gums with a toothbrush or irritating toothpaste
  • feeling tired, stressed or anxious

Sometime they're triggered by things you cannot always control, such as:

  • hormonal changes – such as during pregnancy
  • your genes – some families get mouth ulcers more often
  • a long-term condition – such as inflammatory bowel disease (IBD), coeliac disease or Behçet's disease
  • a vitamin B12 or iron deficiency
  • medicines – including some NSAIDs, beta blockers or nicorandil
  • stopping smoking – people may develop mouth ulcers when they first stop smoking
Content supplied by the NHS website