Mouth Ulcers
Mouth ulcers are small, painful sores that develop on the soft tissue inside the mouth. They're common and usually heal on their own within one to two weeks
About mouth ulcers
Mouth ulcers (aphthous ulcers) occur when the lining of the mouth breaks down, often triggered by minor injury (biting the cheek), stress, certain foods, hormonal changes, or nutritional deficiencies such as low iron, B12 or folate. Most are harmless, though they can be uncomfortable, especially when eating or talking
Treatments
Symptoms
• A small, round or oval sore, usually white or yellow with a red border
• Pain or a burning sensation, especially with certain foods
• Discomfort while eating, drinking or talking
• Occasionally, mild swelling of nearby lymph nodes
• Recurrent ulcers in some people
Diagnosis
Mouth ulcers are usually diagnosed from their appearance alone. An ulcer that lasts longer than three weeks, is unusually large, or keeps recurring should be assessed to rule out an underlying cause or, rarely, something more serious
Treatment
Topical gels or pastes containing local anaesthetic or corticosteroid can ease pain and speed healing. Antimicrobial mouthwash can reduce the risk of secondary infection. Addressing an underlying trigger, such as a nutritional deficiency, helps prevent recurrence
Prevention and self-care
• Avoid hard, spicy, salty or acidic foods that irritate the mouth
• Use a soft-bristled toothbrush
• Manage stress where it's a trigger
• Eat a balanced diet with adequate iron, B12 and folate
• Avoid known trigger toothpaste ingredients (such as sodium lauryl sulfate) if sensitive
• See a dentist if ulcers are frequent or persistent
Reviewed by Hamza Iqbal Naheed, Superintendent Pharmacist, GPhC 2209194 (check the register) · Last updated 21 September 2026