Mouth ulcers


While mouth ulcers are very common and normally clear up on their own, they can be uncomfortable and irritating. They're small sores (or lesions) that can appear anywhere in the mouth and may take a week or two to heal. 

What are mouth ulcers?

Mouth ulcers usually affect the inside of the lips and cheeks, but they can also appear on the tongue and gums. They appear as small, round or oval sores. They're usually off-white or pale yellow and the surrounding area is often red and inflamed. They can be flat or raised, and might grow in size before disappearing. Depending on where it is, a mouth ulcer can cause discomfort and stinging pain when you eat, drink or brush your teeth.

What causes mouth ulcers?

Mouth ulcers most frequently appear when the lining of the mouth (the mucous membrane) is damaged and fails to heal properly. These are called 'traumatic ulcers'. Common causes include:

  • Accidentally, or habitually, biting your cheek, lips or tongue
  • Wearing ill-fitting dentures or braces that rub
  • Having sharp or broken teeth
  • Over-vigorous tooth brushing
  • Burns, from food or drink that's too hot

Addressing or avoiding these common causes of mouth ulcers are the best way to prevent a recurrence.

However, some mouth ulcers are not caused by trauma but by underlying causes, such as:

  • Hormonal change (such as during adolescence or pregnancy)
  • A deficiency, such as vitamin B12 or iron
  • A reaction to medicine (such as ibuprofen)
  • Giving up smoking (ulcers may occur in the first few weeks) 

How can I get rid of a mouth ulcer?

Most mouth ulcers can be managed at home, without the need to visit your dentist or Doctor. Most of the time they'll heal on their own. 

If a mouth ulcer is causing you pain or discomfort, speak to your pharmacist. They may be able to recommend a protective paste or a painkilling gel to ease your discomfort. These commonly create a barrier over the ulcer to allow it to heal and aim to reduce pain and inflammation while preventing infection. 

Your pharmacist may also recommend mouthwashes and lozenges that you can try. None of these can cure your ulcer, but may give you relief from the symptoms while it heals.

Most of the methods you can use to manage a mouth ulcer are non-medical, and include:

  • Using a soft-bristled toothbrush 
  • Consider changing your toothpaste – it may be causing irritation
  • Avoiding spicy, salty or acidic food and drink
  • Using a straw for drinks

Should I worry about mouth ulcers? 

Mouth ulcers can be a sign you have an underlying medical condition, although this is unusual. Mouth ulcers can very occasionally be a symptom of:

  • Mouth cancer (in very rare cases)
  • Hand, foot and mouth disease (a common childhood viral infection that can also affect adults)
  • Lichen planus (an inflammatory condition that appears as a rash on the inside of your mouth and other parts of the body)
  • Ulcerative colitis (an inflammatory bowel condition)

If you have ulcers that come back frequently, are very severe, appear infected or that don't heal after three weeks, you should visit your Doctor. You should also see your Doctor if you suspect ulcers are connected to an underlying cause.

Next steps

  • Avoid or address the cause of most ulcers – broken or sharp teeth, ill-fitting dentures or braces and biting the inside of your cheek or lips
  • If you have an ulcer, use a straw for drinks and avoid salty, spicy and acidic foods
  • If you have ulcers that keep coming back, or one that doesn't heal after three weeks, see your Doctor