A Answers (2)
A white coating on your tongue, especially on the back, could be caused by post-nasal drip. The tongue can get coated with bacteria-rich mucus, giving it a white appearance. You can gently brush your tongue with your toothbrush or use a tongue scraper to reduce the coating and any odor associated with it. If the problem won't go away, see your dentist. You could have a condition such as oral thrush, caused by an overgrowth of fungus.
Jonathan B. Levine, DMD, Dentistry, answeredA normal tongue is pink, textured, and slightly moist. When you stick out your tongue, if you see a white coating -- that is dead bacteria that create an oxygen free zone underneath where the bad breath causing bacteria can thrive. Under this white coating, within the deep papillae of the tongue, the volatile sulfa compounds, which create the offensive odor, are produced.