Most mouth ulcers are harmless and heal within a week or two without treatment. They hurt out of proportion to their size, make eating and drinking unpleasant, and are one of the top five reasons people ask for advice at the pharmacy counter. What the pharmacist offers depends less on the ulcer itself than on how long it has been there, how often you get them, and what else is going on.
Types of ulcer the pharmacist will recognise
Minor aphthous ulcers. Round or oval, under 10 mm across, on the cheek, lip or tongue. Heal in 7 to 14 days. Affect one in five adults at some point.
Major aphthous ulcers. Larger than 10 mm, deeper, heal slowly over weeks and can scar. Need a GP or dental review.
Herpetiform ulcers. Clusters of tiny painful ulcers. Often mistaken for a viral infection. Need a GP.
Traumatic ulcers. Caused by braces, dentures, a broken tooth or an accidental bite. Usually heal quickly once the cause is removed.
What the pharmacy offers
Antiseptic rinses
Chlorhexidine 0.2% mouthwash (Corsodyl and generics) is the most-used first-line product. It reduces infection risk and speeds healing. Use twice a day after brushing, not within 30 minutes of toothpaste, because the foaming agent in toothpaste reduces its effect. A brown stain on teeth and temporary taste changes are common with longer use.
Local anaesthetic gels and sprays
Benzocaine gels, lidocaine gels and Difflam (benzydamine) spray reduce pain enough to allow eating. Difflam has anti-inflammatory as well as numbing effects. Not suitable in young children without pharmacist advice.
Topical corticosteroids
Hydrocortisone 2.5 mg buccal tablets dissolve on the ulcer and dampen inflammation. They do not shorten healing dramatically but reduce pain and size. Beclometasone inhaler sprayed directly onto the ulcer is another option — this is off-label but occasionally suggested by GPs for stubborn ulcers.
Protective pastes and gels
Gels containing salicylates (such as Bonjela Complete Plus) or polyvinylpyrrolidone form a protective layer. Choline salicylate products are not licensed for children under 16 because of Reye's syndrome risk.
What the pharmacist will ask before recommending treatment
- How long has the ulcer been there?
- How many have you had in the last year?
- Do they heal between episodes?
- Any other symptoms: weight loss, tiredness, joint pain, eye problems, diarrhoea, skin rash?
- Any new medicines — some drugs including methotrexate, nicorandil and certain blood pressure tablets cause mouth ulcers.
Repeated ulcers can point to an underlying issue: iron, folate or vitamin B12 deficiency, coeliac disease, Crohn's disease, Behçet's disease, or a reaction to toothpaste containing sodium lauryl sulphate.
Red flags that need same-week review
See a GP or dentist promptly if:
- An ulcer has been present for more than three weeks without healing.
- You have unexplained weight loss, tiredness, or night sweats.
- The ulcer is painless, hard, or has a raised edge.
- There is numbness in the mouth or face.
- You smoke, drink heavily, or chew tobacco or areca nut.
- You have a lump in the neck.
Persistent, painless or atypical ulcers can rarely be mouth cancer. NHS guidance is a two-week wait referral for any ulcer lasting more than three weeks. Catching it early matters.
Self-care that actually helps
- Use a soft toothbrush and avoid sharp or salty foods while an ulcer is active.
- Rinse with salty water (half a teaspoon of salt in a cup of warm water) two to three times a day.
- Check whether switching to a sodium-lauryl-sulphate-free toothpaste reduces recurrence.
- Stop smoking — long-term it reduces ulcer frequency and is the single biggest thing you can do for mouth health.
Finding help
Community pharmacists can advise on ulcer treatment and tell you when to escalate. Use PharmSee's pharmacy directory to find one nearby.
Sources
- NHS: Mouth ulcers
- NICE Clinical Knowledge Summaries: Aphthous ulcer
- British National Formulary: chlorhexidine, hydrocortisone buccal tablets, benzydamine
- NHS England: Suspected cancer referral guidelines