What Is Black Hairy Tongue?

Black hairy tongue refers to a number of conditions of humans and animals that cause the tongue to become unusually dark and/or hairy in appearance.

Black hairy tongue in humans is a harmless condition caused by a fungus which grows on the top surface of the tongue. It is associated with the elderly, as well as with antibiotic use. It is more commonly seen in tobacco smokers. While black is the most common color associated with the condition other colors are also possible.