Overview
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.
Review Date 4/3/2025
Updated by: Ashutosh Kacker, MD, FACS, Professor of Clinical Otolaryngology, Weill Cornell Medical College, and Attending Otolaryngologist, New York-Presbyterian Hospital, New York, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.