Yellow tongue: What causes it?

A yellow tongue is caused by enlargement of the tiny projections (papillae) on the surface of the tongue, which can occur in otherwise healthy people. The yellow color typically results from the production of pigments (porphyrins) made by certain types of bacteria in the mouth. Occasionally, these pigments may also have a brown or black appearance.

A yellow tongue usually is a temporary, harmless problem. Many things can cause enlargement of the papillae, including smoking, mild dehydration, fever or mouth breathing such as due to nasal congestion.

If the discoloration bothers you, try gently brushing your tongue with a solution that is 1 part hydrogen peroxide and 5 parts water. Rinse your mouth with water afterward. Quitting smoking and increasing fiber in your diet may also help.