Pronounced: ap-thus ul-sirsEn Español (Spanish Version)
Aphthous ulcers are also known as canker sores. They are painful, temporary sores that may occur anywhere in the mouth. The sores can occur one at a time or as a group. Canker sores are generally not serious.
Canker Sores in the Mouth
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No one knows exactly what causes canker sores. They are thought to result from an overreaction of the immune system.
Canker sores are not a form of the herpes virus. Unlike herpes, canker sores cannot spread from one person to another.
Last reviewedDecember 2014by Marcin Chwistek, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.