Canker Sore by Ray Sahelian, M.D.

Canker sores are painful blisters that often appear on the inside of the cheeks or lips, under the tongue, or on the gums. They affect people most frequently during their teenage years and into their 20s, and tend to affect women more than men. Canker sores are also called aphthous ulcers. For a list of skin conditions, see skin.

Canker sore cause
Stress, menstrual cycles, poor diet or food allergies may trigger canker sores in some people.

Prevent canker sore
Stay away from toothpastes and mouthwashes that contain irritating ingredients.
Avoid chewing gum and very hard, crunchy or spicy food.
Keep your mouth clean by flossing regularly and brushing after every meal.