OverviewBlack hairy tongue is produced when the papilla (finger-like projections from the surface of the tongue) fail to fall off as they normally do. As the length of the papilla increase, debris collects and bacteria grow, producing the characteristic dark "furry" appearance.
Update Date 2/3/2015
Updated by: Alan Lipkin, MD, otolaryngologist, private practice, Denver, CO. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.