Printer Logo

Mouth sores

Mouth sores
Fever blister


There are different types of mouth sores. They can occur anywhere in the mouth including bottom of the mouth, inner cheeks, gums, lips, and tongue.

Alternative Names

Aphthous stomatitis; Herpes simplex; Cold sores


Mouth sores may be caused by irritation from:

Cold sores are caused by the herpes simplex virus . They are very contagious. Often, you will have tenderness, tingling, or burning before the actual sore appears. Cold sores most often begin as blisters and then crust over. The herpes virus can live in your body for years. It only appears as a mouth sore when something triggers it, such as:

Canker sores are not contagious. They may look like a pale or yellow ulcer with a red outer ring. You may have 1, or a group of them. Women seem to get them more than men. The cause of canker sores is not clear. It may be due to:

Less commonly, mouth sores can be a sign of an illness, tumor, or reaction to a medicine. This can include:

Drugs that may cause mouth sores include aspirin, beta-blockers, chemotherapy medicines, penicillamine, sulfa drugs, and phenytoin.

Home Care

Mouth sores often go away in 10 to 14 days, even if you do not do anything. They sometimes last up to 6 weeks. The following steps can make you feel better:

For canker sores:

Over-the-counter medicines, such as Orabase, can protect a sore inside the lip and on the gums. Blistex or Campho-Phenique may provide some relief of canker sores and fever blisters, especially if applied when the sore first appears.

Acyclovir cream 5% can also be used to help reduce the duration of the cold sore.

To help cold sores or fever blisters, you can also apply ice to the sore.

You may reduce your chance of getting common mouth sores by:

If you seem to get canker sores often, talk to your provider about taking folate and vitamin B12 to prevent outbreaks.

To prevent cancer of the mouth:

Wear a wide-brimmed hat to shade your lips. Wear a lip balm with SPF 15 at all times.

When to Contact a Medical Professional

Call your health care provider if:

What to Expect at Your Office Visit

The provider will examine you, and closely check your mouth and tongue. You will be asked questions about your medical history and symptoms.

Treatment may include:


Daniels TE, Jordan RC. Diseases of the mouth and salivary glands. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 425.

Review Date: 8/5/2015
Reviewed By: Sumana Jothi MD, specialist in laryngology, Clinical Instructor UCSF Otolaryngology, NCHCS VA, SFVA, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.