HealthInfo West Coast-Te Tai Poutini

Mouth ulcers

Kōmaoa ā-waha

Mouth ulcers are very common, affecting around 1 in 5 people.

Most mouth ulcers will heal in around 10 to 14 days, but they can be very painful. If your ulcer has not gone away after 3 weeks, you should see your dentist or general practice team.

Causes of mouth ulcers

There are several possible causes of mouth ulcers.

• Trauma to your mouth such as accidentally biting the inside of your mouth. Or an injury from a broken tooth, badly fitting dentures or brushing your teeth.
• Burning the inside of your mouth with hot food or drink.
• A food intolerance or allergy.

Things that increase your chance of having ulcers include:

• a nutrient deficiency such as low vitamin B12 or iron
• hormone changes such as from your menstrual cycle or pregnancy
• stress
• having another health condition such as coeliac disease, Crohn's disease or a weakened immune system
• some medicines including non-steroidal anti-inflammatories (NSAIDs) (for example, ibuprofen) and beta blockers.

Symptoms of mouth ulcers

Symptoms include:

• a shallow, pale crater inside your lip or in your mouth
• pain, especially when eating or drinking.

You can get several mouth ulcers at the same time.

Diagnosing mouth ulcers

You can diagnose a mouth ulcer from its appearance.

If your ulcer does not get better within 3 weeks or looks unusual, see your healthcare provider.

Also see your healthcare provider if you get lots of ulcers and they keep coming back.

Self-care for mouth ulcers

• Use a mouthwash made by putting ½ teaspoon salt in a glass of warm water. Rinse your mouth with this then spit it out. You can use this as often as you like.
• Eat soft foods and use a straw for drinking.
• Avoid hot, spicy and hard foods.
• Take paracetamol for pain.

Treating mouth ulcers

If the simple measures above are not enough, there are several medicines you can try. Your pharmacist can give you advice on these. Options include:

• antiseptic mouthwash such as chlorhexidine
• protective pastes
• steroid containing pastes
• local pain relief including sprays, mouthwashes and ointments.

Preventing mouth ulcers

You can reduce your chances of getting mouth ulcers by:

• getting any damaged teeth or ill-fitting dentures fixed
• not smoking
• avoiding food that trigger your ulcers
• eating well including getting enough iron.

  HealthInfo recommends the following pages

• DermNet NZ – Mouth ulcers

  Mouth ulcers and how they are treated.

Written by HealthInfo clinical advisers. Last reviewed March 2025.

Sources

Page reference: 75114

Review key: HIDRY-74891