URL of this page: //www.nlm.nih.gov/medlineplus/ency/article/001448.htm

Mouth ulcers

Mouth ulcers are sores or open lesions in the mouth.


Mouth ulcers are caused by many disorders. These include:

A skin sore caused by histoplasmosis may also appear as a mouth ulcer.


Symptoms will vary, based on the cause of the mouth ulcer. Symptoms may include:

  • Open sores in the mouth
  • Pain or discomfort in the mouth

Exams and Tests

Most of the time, a health care provider or dentist will look the ulcer and where it is in the mouth to make the diagnosis. You may need blood tests or a biopsy of the ulcer may be needed to confirm the cause.


The goal of treatment is to relieve symptoms.

  • The underlying cause of the ulcer should be treated if it is known.
  • Gently cleaning your mouth and teeth may help relieve your symptoms.
  • Medicines that you rub directly on the ulcer such as antihistamines, antacids, and corticosteroids may help soothe discomfort.
  • Avoid hot or spicy foods until the ulcer is healed.

Outlook (Prognosis)

The outcome varies depending on the cause of the ulcer. Many mouth ulcers are harmless and heal without treatment.

Some types of cancer that may first appear as a mouth ulcer that does not heal.

Possible Complications

  • Cellulitis of the mouth, from secondary bacterial infection of ulcers
  • Dental infections (tooth abscesses)
  • Oral cancer
  • Spread of contagious disorders to other people

When to Contact a Medical Professional

Call your health care provider if:

  • A mouth ulcer does not go away after 3 weeks
  • You have mouth ulcers return often, or if new symptoms develop


To help prevent mouth ulcers and complications from them:

  • Brush your teeth at least twice a day and floss once a day.
  • Get regular dental cleanings and checkups.

Alternative Names

Oral ulcer; Stomatitis - ulcerative; Ulcer - mouth


Daniels TE. Diseases of the mouth and salivary glands. In: Goldman L, Schafer AI, eds.Goldman's Cecil Medicine.

Mirowski GW, Mark LA. Oral disease and oral-cutaneous manifestations of gastrointestinal and liver disease. In: Feldman M, Friedman LS, Brandt LJ, eds.Sleisenger & Fordtran's Gastrointestinal and Liver Disease.

Update Date 1/21/2013

Related MedlinePlus Health Topics