Black tongue will not die, this is a very common situation, the most likely food or drug staining, such as mulberry, bismuth potassium citrate, etc., especially some lozenges, is very likely to occur such a situation. As long as you rinse your mouth regularly and brush your tongue gently when you brush your teeth, you will gradually get better and it is not a particularly significant disease. It is not a major disease. Eat a lighter diet and eat more vegetables and fruits. If it does not improve for a long time, you can visit a doctor for an examination, and if it is a fungal infection, you can undergo antifungal treatment.