Mouth Ulceration

Key facts

• Mouth ulcers are small, painful sores that form on the inner lining of the cheeks, lips, tongue, or gums. Most heal on their own within one to two weeks.
• Minor aphthous ulcers, the most common type, usually have no single cause. Triggers include physical trauma, stress, hormonal shifts, nutritional deficiencies (especially vitamin B12, folate, and iron), and certain foods.
• Self-care, salt-water rinses, avoiding spicy or acidic food, a soft toothbrush, and topical anaesthetic or anti-inflammatory gels, resolves most straightforward ulcers.
• See a doctor if an ulcer has not healed after three weeks, is unusually large, keeps returning, or comes with fever or difficulty swallowing.

What triggers them

Minor aphthous ulcers, the most frequent type, typically have no single identifiable cause. Common triggers include physical trauma such as biting the cheek or ill-fitting dental work, stress, hormonal shifts, nutritional deficiencies (especially vitamin B12, folate, and iron), and certain foods. Dehydration can also play a role in some cases.

Easing the pain

Self-care usually resolves a straightforward ulcer:

• Rinse with warm salt water or a dilute antiseptic mouthwash several times a day.
• Avoid very spicy, salty, or acidic foods until the sore heals.
• Use a soft toothbrush to avoid aggravating the site.
• Apply a topical anaesthetic or anti-inflammatory gel directly to the ulcer to reduce pain.

When to see a doctor

See a doctor if an ulcer has not healed after three weeks, is unusually large, keeps returning, or is accompanied by fever or difficulty swallowing. Persistent mouth ulceration can occasionally signal an underlying condition that needs investigation, so recurring or non-healing sores are worth checking rather than treating indefinitely at home.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.