Summary

Canker sores are small, round sores in your mouth. They can be on the inside of your cheek, under your tongue, or in the back of your throat. They usually have a red edge and a gray center. They can be quite painful. They are not the same as cold sores, which are caused by herpes simplex.

Canker sores aren't contagious. They may happen if you have a viral infection. They may also be triggered by stress, food allergies, lack of vitamins and minerals, hormonal changes or menstrual periods. In some cases the cause is unknown.

In most cases, the sores go away by themselves. Some ointments, creams or rinses may help with the pain. Avoiding hot, spicy food while you have a canker sore also helps.

Learn More

• Canker Sore (Mayo Foundation for Medical Education and Research) Also in Spanish
• Canker Sore (Aphthous Ulcer) (VisualDX)
• Canker Sores (American Academy of Family Physicians) Also in Spanish
• Canker Sores (Nemours Foundation) Also in Spanish
• Canker Sores (American Academy of Oral Medicine) Also in Spanish
• Canker Sores (For Parents) (Nemours Foundation) Also in Spanish
• Canker Sores: Treatment (American Academy of Oral Medicine) Also in Spanish

Clinical Trials

• ClinicalTrials.gov: Stomatitis, Aphthous (National Institutes of Health)

Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)

• Article: Transcriptomic signatures of host immune responses in aphthous ulcers, the earliest...
• Article: Anxiety and small intestinal bacterial overgrowth: associations with recurrent aphthous ulcers.
• Article: Colchicine treatment in PFAPA: how long should we wait for the...
• Canker Sores -- see more articles

Patient Handouts

• Canker sore (Medical Encyclopedia) Also in Spanish