What causes a black hairy tongue?

Tongue papillae: The tongue is coated with taste receptors termed papillae. These normally stay short from food chewing and constant rubbing in normal activity of the mouth. If they grow longer, they can be stained darker by food and other substances in the mouth. It is not harmful and is not pathologic. You can lessen it by brushing the tongue as well as your teeth with your toothbrush.

Overgrown papillae: The tongue is coated with taste receptors termed papillae. These normally stay short from food chewing and constant rubbing in normal activity of the mouth. If they grow longer, they can be stained darker by food and other substances in the mouth. It is not harmful and is not pathologic. You can lessen it by brushing the tongue as well as your teeth with your toothbrush.

Papillae overgrowth: The tongue is coated with taste receptors termed papillae. These normally stay short from food chewing and constant rubbing in normal activity of the mouth. If they grow longer, they can be stained darker by food and other substances in the mouth. It is not harmful and is not pathologic. You can lessen it by brushing the tongue as well as your teeth with your toothbrush.