Thrush is an infection of the mouth. It usually begins on the tongue and inside of the cheeks, and spread to the roof of the mouth, gums, tonsils, and throat.

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Thrush is caused by yeast, a type of fungus. The immune system can normally fight off this fungus but the fungus can grow and spread if the immune system is weakened.

Risk Factors

Certain situations can weaken the immune system or change the normal bacterial balance in the mouth or body. These changes increase the risk of thrush. Other factors include:

  • Health conditions such as:
    • HIV infection
    • Diabetes
    • Certain types of cancer
  • Certain medications such as:
    • Oral or inhaled corticosteroids
    • Medications that treat psychiatric conditions
    • Antibiotics
  • Imbalance of healthy bacteria in the mouth which can be caused by:
    • Wearing dentures or mouth guards
    • Prolonged illness
    • Conditions that cause a dry mouth


In some cases, you may not have symptoms. In those that have symptoms, thrush may cause:

  • White or red patches on the inside of the cheeks or tongue that may or may not come off when rubbed
  • Sore mouth or throat
  • Difficulty swallowing
  • Differences in taste
  • Fissures or cracks in the mouth

Thrush can spread beyond the mouth. Complications include infections that spread to the:

  • Esophagus—the tube that carries food from the mouth to the stomach
  • Urinary tract
  • Whole body— sepsis causes multiple organ failure and death


Your doctor will ask you about your symptoms and medical history. A physical exam will be done, including an inspection of your mouth. Diagnosis can usually be made based on your symptoms. Your doctor may take a sample of cells from the affected area to examine under a microscope.


The goal of treatment is to restore the normal balance of bacteria and yeast in the mouth. If any underlying conditions contribute to thrush, they will also be treated.

Treatments include:


Antifungal medications are used to treat thrush. Medications come in the form of tablets, rinses, or lozenges that dissolve in the mouth.

If you wear dentures, clean and brush them daily. You also need to clean the inside of your mouth and tongue with a soft-bristled toothbrush.

Proper Oral Hygiene

Oral hygiene practices may aid in healing. This includes:

  • Rinsing your mouth out with salt water
  • Gently scraping off patches with a toothbrush
  • Brushing your teeth at least twice a day
  • Flossing your teeth at least once a day


To help reduce your chances of thrush:

  • Maintain proper oral hygiene.
  • Limit your use of mouthwashes and mouth sprays. These can upset the normal balance of yeast and bacteria in your mouth.
  • If you use a corticosteroid inhaler or nasal spray, rinse your mouth thoroughly after each use.

Centers for Disease Control and Prevention

National Foundation for Infectious Diseases


Canadian Dental Association

Public Health Agency of Canada


Adults under 40. Mouth Healthy—American Dental Association website. Available at: Accessed December 14, 2017.

Candida infections of the mouth, throat, and esophagus. Centers for Disease Control and Prevention website. Available at: Updated August 4, 2017. Accessed December 14, 2017.

Dentures. Mouth Healthy—American Dental Association website. Available at: Accessed December 14, 2017.

Kelland, K. Unregulated Antibiotic Sales May Increase Risk of “Superbugs”—UK Review. Clinical Infectious Diseases. 2016;62(3):i-iii. Available at:

Ohnmacht GA, Phan GQ, Mavroukakis SA, et al. A prospective, randomized, double-blind, placebo-controlled trial evaluating the effects of nystatin on the development of oral irritation in patients receiving high-dose intravenous interleukin-2. J Immunother. 2001;24(2):188-192.

Oral candidiasis. EBSCO DynaMed Plus website. Available at: Updated April 27, 2017. Accessed December 14, 2017.

Last reviewed November 2018 by EBSCO Medical Review Board Marcie L. Sidman, MD  Last Updated: 12/14/2017