If the blackening of the toenail root is caused by many changes such as extrusion and stimulation, it is possible that the nail is bruised and the capillaries under the nail are broken. It will expand within a short period of time, grow outward over time, and gradually fall off after 6-7 months of metabolism. If the black changes at the root of the toe have obvious protrusions and will become stripe-like growth over time, gradually spreading to the tip of the nail, it may be a nail nevus, which is one of the nail nevi and has a high probability of malignancy. It is recommended that surgery should be performed to remove the nevus, and pathological tests should be done to clarify the nature of the disease, and if necessary, secondary enlargement can be performed.