How to heal a sore in my mouth

Mouth ulcers are common and should clear up on their own within a week or 2. But see a GP or dentist if you have a mouth ulcer that lasts longer than 3 weeks.

How you can treat mouth ulcers yourself

Mouth ulcers are rarely a sign of anything serious, but may be uncomfortable to live with.

They 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 tablet, mouthwash, gel or spray
  • corticosteroid lozenges
  • a salt (saline) mouthwash

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

How to rinse with salt mouthwash

  1. Dissolve half a teaspoon of salt in a glass of warm water – warm water helps salt dissolve.
  2. Rinse your mouth with the solution, then spit it out – do not swallow it.
  3. Repeat as often as you like.

Find a pharmacy

Non-urgent advice: See a dentist or GP if your mouth ulcer:

  • lasts longer than 3 weeks
  • keeps coming back
  • grows bigger than usual or is near the back of your throat
  • bleeds or 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.

Treatment from a dentist or GP

A GP or dentist may prescribe stronger medicine to treat severe, persistent or infected mouth ulcers.

Possible treatments include:

  • steroid mouth spray or steroid tablets that dissolve in your mouth
  • painkilling gels, ointments, sprays or tablets
  • mouthwashes to kill or remove any germs in your mouth

Check if you have a mouth ulcer

How to heal a sore in my mouth
Mouth ulcers usually appear inside the mouth, on the cheeks or lips.
How to heal a sore in my mouth
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.

Causes of 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

Sometimes 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 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

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

  • hand, foot and mouth disease, which also causes a rash on the hands and feet
  • oral lichen planus, which causes a white, lacy pattern inside the cheeks
  • Crohn's disease and coeliac disease (conditions that affect the digestive system)
  • a weakened immune system from having a condition like HIV or lupus

Page last reviewed: 19 January 2021
Next review due: 19 January 2024

How long does it take for mouth sores to heal?

Mouth sores often go away in 10 to 14 days, even if you do not do anything. They sometimes last up to 6 weeks. The following steps can make you feel better: Avoid hot beverages and foods, spicy and salty foods, and citrus.

What causes sores in the mouth?

Food sensitivities, particularly to chocolate, coffee, strawberries, eggs, nuts, cheese, and spicy or acidic foods. A diet lacking in vitamin B-12, zinc, folate (folic acid) or iron. An allergic response to certain bacteria in your mouth. Helicobacter pylori, the same bacteria that cause peptic ulcers.