Are Canker Sores Herpes?


Canker sores are not related, in any way, to herpes.

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Disclaimer: This information isn’t a substitute for professional medical advice, diagnosis, or treatment. You should never rely upon this article for specific medical advice. If you have any questions or concerns, please talk to your doctor.

If you’ve ever found a painful, little sore in your mouth, you may have wondered about what was going on. Is that a canker sore or a cold sore, and what’s the difference anyway? Are both types of sores related to herpes?

What Causes Cold Sores?

Cold sores are painful lesions that occur on the lips and around the mouth, caused by Herpes Simplex Virus type 1 (HSV-1) and infrequently by HSV-2. Though most people with HSV-1 never (or rarely) experience an outbreak, it is quite contagious, and about half of the population in the U.S. (aged 14-49) carry this virus. If you have cold sores, your doctor may prescribe antiviral medication to treat outbreaks, or s/he may put you on a preventive regimen (1).

What are Canker Sores?

Canker sores, also called aphthous ulcers, are round or oval sores that usually occur on membranous tissue in the mouth—the pink insides of the lips, the tongue, or the insides of the cheeks. In some cases, canker sores can occur on the genitals, but these are not sexually transmitted sores (2).

Unlike cold sores, canker sores are not caused by herpes and are not transmissible. Frequent or more severe canker sores can indicate underlying immunologic issues, but run-of-the-mill canker sores are most commonly associated with stress, dietary changes, certain medications, and trauma (3) (such as accidentally biting your cheek when eating—we’ve all been there).

In most cases, canker sores will clear up on their own without treatment, but you may benefit from topical therapies that can help relieve pain and inflammation. For more severe cases, your doctor may prescribe an antibiotic mouth rinse or a topical or systemic corticosteroid treatment (3).

In short, canker sores are not related, in any way, to herpes.


  1. Herpes simplex virus. World Health Organization. Published January 31, 2017. Accessed March 18, 2019.
  2. Ngan V. Aphthous ulcer. Aphthous ulcer | DermNet NZ. Published 2003. Accessed March 24, 2019.
  3. Akintoye SO, Greenberg MS. Recurrent aphthous stomatitis. Dental Clinicians of North America. Published January 21, 2014. Accessed March 24, 2019.

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