Mouth ulcers are small, painful sores inside the mouth, on the gums, tongue or inside of the cheeks and lips. The common type (aphthous ulcers) is round or oval, white or yellow with a red edge, and heals by itself in 1 to 2 weeks. They are not contagious. An ulcer that does not heal within 3 weeks must be checked by a doctor or dentist.
Symptoms
One or more painful round sores inside the mouth
White, grey or yellow centre with a red border
Pain when eating, drinking or brushing, especially with salty, spicy or sour food
Tingling or burning before the sore appears
In children with viral infections, many sores with fever and drooling
Causes
Biting the cheek, a sharp tooth, a rough denture or brushing too hard
Stress, tiredness or hormone changes around periods
Lack of iron, vitamin B12 or folic acid
Viral infections such as cold sores or hand, foot and mouth disease
Some toothpastes, foods or medicines
Less often, illnesses of the gut or immune system
Prevention
Use a soft toothbrush and brush gently
Have sharp teeth or rough dentures fixed by a dentist
Eat a balanced diet with iron-rich foods, fruit and vegetables
Avoid foods that seem to trigger ulcers
Manage stress and get enough sleep
Treatment
Most ulcers heal on their own within 1 to 2 weeks
Rinse with warm salt water several times a day
Avoid spicy, salty, sour and very hot food until healed
Pain-relieving gels or mouthwashes from the pharmacy
Paracetamol for pain if needed
Treatment of any deficiency, such as iron or vitamin B12, found on blood tests
Common questions
Are mouth ulcers caused by "heat" in the body?
No. Ulcers are usually caused by injury, stress, low iron or vitamins, or viruses, not by "hot" or "cold" foods. A balanced diet helps, but avoiding particular foods is only useful if they clearly trigger your ulcers.
Can I spread mouth ulcers by sharing a cup?
Common aphthous ulcers are not contagious. Cold sores caused by the herpes virus can spread, so do not share cups or kiss children while you have a cold sore.
