why would your tongue turn black?
(Thinkstock Images/Stockbyte/Getty Images) Your tongue can turn black if you have eaten something that has stained it. Black licorice can stain your tongue, as can chewing tobacco. Products that contain bismuth can temporarily turn your tongue black, according to Atlas of Adult Physical Diagnosis.. Jupiterimages/liquidlibrary/Getty Images.
A black or brown tongue typically is due to the overgrowth of bacteria that normally are present on the tongue. This, too, can be caused by the killing of some bacteria with antibiotics so other bacteria overgrow. But the most common cause of discoloration of the tongue is the overgrowth of a fungus. The most common fungus is called candida. But overgrowth of the candida fungus turns the tongue white. Infection with candida is called candidiasis, and when it happens on the tongue the condition is called thrush.
Now, if your child didn't take Pepto-Bismol or another medication with bismuth sub-salicylate that could have turned his tongue black, then you should likely see your pediatrician. In addition to black hairy tongue, a child with a black tongue could possibly have: a pigmented nevus of the tongue.