Eat fermented foods and drink probiotic beverages to bring your inner ecosystem back into balance. 1  Use the Principle of 80/20 at every meal. 2  Warm up your digestion with cooked foods. 3  Add herbs and spices to improve digestion. 4  Drink warm ginger tea 20 minutes before a meal to benefit digestion and relieve nausea.
A black hairy tongue is caused by too much bacteria or yeast growth in the mouth. The bacteria build up on tiny rounded projections called papillae. These lie along the surface of the tongue. Instead of shedding as they normally do, the papillae start to grow and lengthen, creating hair-like projections.
Your tongue can turn black if you have eaten something that has stained it. Black licorice can stain your tongue, as can chewing tobacco. If you have a black tongue, then you could have a fungus called Aspergillus niger growing on the surface of your tongue. If you have too much bacteria growing in your mouth, it could cause your tongue to appear black and hairy, according to the Mayo Clinic.