Black hairy tongue is the lengthening of papillae which are bumps on the surface of the tongue. Usually the ends of the papillae get rubbed away by food but sometimes they grow much longer than normal, making the tongue look furry. The extra tissue can get stained by food or tobacco and become yellowish brown or black.
Even though it may appear alarming, black hairy tongue itself is harmless (although it is thought to be linked to the development of thrush[citation needed]). This condition does not involve any type of bacteria or fungi and generally resolves on its own; the recommended treatment is to brush the tongue with a soft toothbrush twice per day. Black hairy tongue is listed as a possible side effect while taking the antibiotic penicillin, also vitamins.
A similar condition can occur within 24 hours after taking Pepto-Bismol, especially chewable tablets, caused by a chemical reaction. It is short-lasting in duration, but may initially cause alarm.
