Mouth Ulcers
A small, round, painful sore that makes every meal a negotiation. Mouth ulcers are very common, affecting up to 1 in 4 people at some point. Most heal by themselves within 2 weeks. One that lasts longer than 3 weeks needs a check.
What they are: most are aphthous ulcers: shallow white or yellow sores with a red edge. Minor ulcers are under about 5 mm and heal in around 2 weeks without scarring. Larger ulcers can take weeks and leave a scar.
Common triggers: biting your cheek, a sharp tooth or brace, burns from hot food, stress and tiredness, hormone changes, stopping smoking, and toothpastes containing sodium lauryl sulphate. They often run in families.
Linked conditions: low iron, B12, folate or zinc, coeliac disease, Crohn’s disease, and, rarely, immune conditions such as Behçet’s disease. Several ulcers at once can also be a virus such as hand, foot and mouth disease.
The mouth ulcer ladder
Most ulcers just need protecting while they heal. Steroid treatments work best if started early; frequent or stubborn ulcers need a search for a cause.
- Step 1 · Self-careProtect and avoid triggersUse a soft toothbrush and a toothpaste without sodium lauryl sulphate. Avoid spicy, salty, acidic, crunchy or very hot food and drink. A salt-water rinse (half a teaspoon in warm water, spat out) can soothe.
- Works
- Eases pain and avoids further damage while the ulcer heals
- Cost
- Free
- How long
- Up to 2 weeks
- Watch for
- Get sharp teeth or rough fillings fixed by a dentist.
Corn chips are a bold choice this week.
- Step 2 · PharmacyAntiseptic or pain-relieving mouthwash and gelsA chlorhexidine mouthwash, or a numbing gel, spray or mouthwash (such as benzydamine) for pain.
- Works
- Chlorhexidine reduces how bad and how long ulcers last, but doesn’t stop them coming back. Numbing products ease pain
- Cost
- About $10–15
- How long
- Until healed
- Watch for
- Check age limits on products for children.
Makes the fortnight more bearable.
- Step 3 · Pharmacy or prescriptionSteroid lozenges, paste or sprayA steroid applied to the ulcer. In the UK some are sold in pharmacies; elsewhere you may need a dentist or GP.
- Works
- The first-line treatment. Works best if started at the first tingle, before the ulcer forms
- Cost
- Varies by product
- How long
- A few days
- Watch for
- Ask a pharmacist, dentist or GP which product suits you.
Timing is everything. Catch it at the tingle.
- Step 4 · GP or dentistCheck and blood testsFor ulcers lasting more than 3 weeks, frequent or severe ulcers, or other symptoms. Your GP may test iron, B12, folate and for coeliac disease.
- Works
- Treating a deficiency or coeliac disease can reduce ulcers
- Cost
- Medicare rebates; blood tests usually covered
- How long
- Weeks
- Watch for
- An ulcer that won’t heal must be checked to rule out mouth cancer.
Sometimes the mouth is reporting on the rest of the body.
- Step 5 · SpecialistStronger treatment for severe ulcersFor large or almost constant ulcers, a short course of steroid tablets or other immune-calming medicines, usually with a specialist.
- Works
- Can help severe cases, with more side effects
- Cost
- Varies
- How long
- Weeks to months
- Watch for
- Ulcers with sore eyes, genital sores, skin or joint problems need a specialist review.
Big guns for the rare big problem.
Save your money
Popular, heavily marketed or often asked about, but the evidence is weak or says no.
- Toothpastes with sodium lauryl sulphateA foaming ingredient that can trigger ulcers in some people. Try a toothpaste without it.
- Waiting it out for more than 3 weeksAn ulcer that won’t heal needs a check by a GP or dentist.
What you can do
- Note when ulcers appear: stress, periods, new toothpaste or a sharp tooth.
- See a dentist for sharp teeth, rough fillings or loose dentures.
- Eat a varied diet with iron and B vitamins.
- If you also have diarrhoea, bloating or weight loss, read our coeliac disease fact sheet.
- For blisters on the lips, see our cold sores fact sheet.
- Keep up regular dental check-ups.
See your GP if
- An ulcer lasts more than 3 weeks
- It looks different from usual: bigger, at the back of the mouth, or bleeding
- It gets more painful and red, which can mean infection
- You get ulcers very often, or several at once
- You also have sore eyes, genital sores, rashes or painful, swollen joints
- You have diarrhoea, weight loss or tiredness as well
The 3-week rule: most mouth ulcers heal within 2 weeks. Any ulcer, lump or patch in the mouth that lasts more than 3 weeks needs checking by a GP or dentist.
Common questions
What causes mouth ulcers?
Often minor injury such as biting your cheek, stress, tiredness, hormone changes or certain toothpastes. Frequent ulcers can be linked to low iron, B12 or folate, or coeliac disease.
How do I make a mouth ulcer heal faster?
Steroid treatments started early, at the first tingle, work best. Antiseptic mouthwash can reduce how bad and how long an ulcer lasts. Avoid spicy, acidic and crunchy foods while it heals.
When is a mouth ulcer serious?
If it lasts more than 3 weeks, keeps bleeding, or comes with other symptoms such as weight loss or joint pain. Long-lasting ulcers need checking to rule out mouth cancer.
Are mouth ulcers contagious?
Common aphthous ulcers are not. Some viruses, such as hand, foot and mouth disease and cold sores, cause sores that are.
Helpful resources
- NHS: Mouth ulcersCauses, treatments and when to get help. Free, UK.
- Coeliac disease fact sheetA cause of frequent ulcers. Free, from us.
- Hand, foot and mouth disease fact sheetWhen ulcers come with spots on hands and feet. Free, from us.
Evidence and more information
maladywise.com/mouth-ulcers/