Black spots on the nail may be caused by the use of black nail dye for coloring, and the nail residue part of the black dye caused, generally use professional nail polish remover, or nail polish remover to clean off the nail residue can be. However, it can also be caused by trauma that causes bleeding under the nail, or nail nevus, limb freckle-like melanoma, etc. The black spots on the nails are of different types and can be solved in different ways. 1. Trauma: The bleeding of capillaries under the nails due to bumping, the blood coalesces into a block and forms black spots, which may not occur at that time and not care about the blood seepage, and later present the above symptoms. For black spots on nails caused by this kind of condition, generally no special treatment is needed, they can be absorbed by themselves, and in serious cases, spray or ointment to activate blood circulation and remove blood stasis, such as safflower oil, can be used to deal with them. 2. Nail nevus: It is a kind of junctional nevus, which can be single or multiple. When the symptoms are mild, it may appear as a black spot on the nail. Usually small nail nevi do not need treatment, but when nodules, ulcers and bleeding appear, they should be treated by surgical excision as soon as possible in order to prevent malignant transformation; 3. Limb freckle-like melanoma: It is a malignant tumor with high malignant degree originated from melanocytes, and is usually found in the palmoplantar, nail and perineal areas. The lesions are unevenly pigmented and irregularly bordered patches. If located in the nail matrix, the nail plate and nail bed may show longitudinal and transverse pigment streaks. It can be treated by surgical excision, and for patients who have metastasized, chemotherapy or radiotherapy can be used to control the disease.