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Are Canker Sores Contagious?

My girlfriend has canker sores. Can I catch them from her?

No. Canker sores are not . Unlike cold sores, you can't catch canker sores from another person.

So how can you tell if a sore is a (non-contagious) canker sore or a contagious cold sore? Cold sores usually develop outside the mouth, around the lips, chin, or nostrils. Canker sores are different: they only develop on the inside of the mouth.

Canker sores go away on their own after a while and usually don't need treatment. But if your girlfriend gets canker sores often, is in a lot of pain, or the sores don't improve within 2 weeks, she should see her doctor.

*Names have been changed to protect user privacy.

Date reviewed: January 2013