A temporary condition in which the tongue appears dark and furry.
Black hairy tongue is a harmless condition. It's caused by a buildup of dead skin cells on the tiny projections that contain taste buds (papillae). Potential causes include antibiotic use and tobacco use.
Symptoms include discoloration of the tongue, a furry or hairy appearance of the tongue, bad breath, and a metallic taste in the mouth.
It often clears up without medical treatment.