Mouth ulcer


Mouth ulcer
Mouth ulcer

If you have a mouth ulcer that lasts longer than three weeks, call your dental practice for advice.

When you contact your dental practice or Health Board for a dental appointment, you MUST tell them if you have tested positive for coronavirus (COVID19) OR you are currently self-isolating OR you have possible symptoms.

Dental practices have to comply with social distancing measures so please do not attend without having made an appointment first.

What are mouth ulcers?

Mouth ulcers are painful sores in the lining of the mouth, which affect some people and are often worse in stressful times. 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.

How you can treat mouth ulcers yourself

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

Avoiding things that irritate your mouth ulcer should help to reduce the discomfort while waiting for the ulcer to heal. Try the following:

  • use a soft-bristled toothbrush when cleaning your teeth
  • drink cool drinks through a straw
  • eat softer foods
  • eat a healthy, balanced diet
  • avoid eating spicy, salty or acidic food
  • avoid eating rough, crunchy food, such as toast or crisps
  • avoid drinking hot or acidic drinks, such as fruit juice
  • try using a toothpaste without sodium lauryl sulphate (SLS)

A pharmacist can help with mouth ulcers

Mouth Ulcers are one of the conditions covered by the Common Ailments Scheme which is an NHS service that patients can access for free advice and free treatment and is available from 99% of pharmacies in Wales. 
Find your nearest pharmacy here. 
Find more information on the service here

Pharmacists can recommend treatments that speed up healing, prevent infection or reduce pain, such as: 

  • antimicrobial mouthwashes 
  • painkilling mouthwashes, gels or sprays 
  • corticosteroid lozenges 

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


If your mouth ulcer lasts longer than three weeks call your dental practice for advice.

In rare cases, mouth ulcers that don’t heal can be a sign of mouth cancer. You should call your dental practice or GP if an ulcer has been present for three weeks or more. They will carry out remote consultation over the phone/video before seeing you in person in the practice if required.

If you do not have a regular dentist you need to call the appropriate dental helpline number for your Local Health Board area.


The information on this page has been adapted by NHS Wales from original content supplied by NHS UK NHS website
Last Updated: 30/11/2022 10:24:49