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

How you can treat mouth ulcers yourself

Mouth ulcers need time to heal and there is 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

A pharmacist can help with mouth ulcers

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

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

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

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.

Check if you have a mouth ulcer

You can’t 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 can’t always control, for example:

  • 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
  • medications – including some NSAIDs, beta-blockers or nicorandil
  • stopping smoking – people may develop mouth ulcers when they first stop smoking