White tongue is a coating of debris, bacteria and dead cells on your tongue that makes it look white. Although the appearance of white tongue may be alarming, the condition is usually harmless and temporary. However, white tongue can be an indication of some serious conditions, ranging from infection to a precancerous condition.

If you're concerned about a white coating or white spots on your tongue, contact your doctor or dentist.

White tongue is the result of an overgrowth and swelling of the fingerlike projections (papillae) on the surface of your tongue. The appearance of a white coating is caused by debris, bacteria and dead cells getting lodged between the enlarged and sometimes inflamed papillae.

Causes of papillae hypertrophy or inflammation include, for example:

• Poor oral hygiene
• Dry mouth
• Dehydration (when the body doesn't have enough water and other fluids to work as it should)
• Smoking or other oral tobacco use
• Alcohol use (excessive)
• Mouth breathing
• Low roughage diet (eating mostly soft or mashed foods)
• Mechanical irritation from sharp tooth edges or dental appliances
• Fever

Examples of conditions associated with white patches or other discolorations of your tongue include:

• Use of certain medications, such as prolonged use of antibiotics that may bring on an oral yeast infection
• Oral thrush
• Geographic tongue
• Leukoplakia
• Oral lichen planus
• Mouth cancer
• Tongue cancer
• Syphilis
• Immunosuppression caused by such diseases as HIV/AIDS

White tongue is generally harmless, and may be helped by gently brushing your tongue with a toothbrush or tongue scraper and drinking plenty of water.

Make an appointment with your doctor or dentist if:

• You're concerned about changes in your tongue
• Your tongue hurts
• Your white tongue persists for longer than a few weeks