Black spots on the tongue are not necessarily cancer, first of all, we should consider whether it is caused by coloring, if it is caused by eating food coloring, usually about a week the black spots will disappear naturally. If the black spot in the mouth for a month or so has not disappeared, and even has signs of getting bigger, we should pay attention to it, and it is likely to be a malignant melanoma. At this time, it is recommended that the patient go to the stomatology department in time to remove the black spot and then carry out pathological diagnosis. If itself is some long time coloring, there is no way to remove, or safer. If it is a malignant melanoma, systemic interferon therapy is also taken. The tongue is a very sensitive and tumor-prone part of the body, and it is important to visit the dentist as soon as you have any lesions.