MedlinePlus Medical Encyclopedia: Canker sore

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Canker sore

A canker sore is a common form of mouth ulcer, which appears as a painful white or yellow ulcer surrounded by a bright red area. A canker sore sore can be triggered by emotional stress, dietary deficiencies, menstrual periods, hormonal changes, food allergies or trauma in the mouth. Canker sores usually heal without treatment within two weeks.

Update Date: 3/11/2004

Updated by: A.D.A.M. Medical Illustration Team

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