A canker sore is a painful, open sore in the mouth. Canker sores are white or yellow and surrounded by a bright red area. They are not cancerous.
A canker sore is not the same as a fever blister (cold sore).
Aphthous ulcer; Ulcer - aphthous
Canker sores are a common form of mouth ulcer. They may occur with viral infections. In some cases, the cause is unknown.
Canker sores may also be linked to problems with the body's immune system. The sores may also be brought on by:
Other things that can trigger canker sores include:
Anyone can develop a canker sore. Women are more likely to get them than men. Canker sores may run in families.
Canker sores most often appear on the inner surface of the cheeks and lips, tongue, upper surface of the mouth, and the base of the gums.
Less common symptoms include:
Pain often goes away in 7 to 10 days. It can take 1 to 3 weeks for a canker sore to completely heal. Large ulcers can take longer to heal.
In most cases, the canker sores go away without treatment.
Try not to eat hot or spicy foods, which can cause pain.
Use over-the-counter medicines that ease pain in the area.
Medicines prescribed by your provider may be needed for severe cases. These may include:
Brush your teeth twice a day and floss your teeth every day. Also, get routine dental check-ups.
In some cases, gastric acid-reducing medicines can decrease the discomfort.
Donato Rigante is in Rome, Italy. Rigante is rated as an Elite expert by MediFind in the treatment of Canker Sore. He is also highly rated in 51 other conditions, according to our data. His top areas of expertise are PFAPA, Mevalonate Kinase Deficiency, TNF Receptor-Associated Periodic Syndrome, and Neonatal Onset Multisystem Inflammatory Disease.
Gerard Espinosa is in Barcelona, Spain. Espinosa is rated as an Elite expert by MediFind in the treatment of Canker Sore. He is also highly rated in 25 other conditions, according to our data. His top areas of expertise are Aphthous Stomatitis, Canker Sore, Antiphospholipid Syndrome, and Behcet Disease.
Luca Cantarini is in Siena, Italy. Cantarini is rated as an Elite expert by MediFind in the treatment of Canker Sore. He is also highly rated in 44 other conditions, according to our data. His top areas of expertise are TNF Receptor-Associated Periodic Syndrome, Aphthous Stomatitis, PFAPA, and Behcet Disease.
Canker sores almost always heal on their own. The pain should decrease in a few days. Other symptoms disappear in 10 to 14 days.
Call your provider if:
Daniels TE, Jordan RC. Diseases of the mouth and salivary glands. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 397.
Dhar V. Common lesions of the oral soft tissues. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 341.
Klatt EC. Head and neck. In: Kumar V, Abbas AK, Aster JC, eds. Robbins and Cotran Atlas of Pathology. 10th ed. Philadelphia, PA: Elsevier; 2021:chap 6.