Darkening of the corners of the mouth can be caused by sun exposure, improper skin cleansing, and liver disease. It can be relieved through the use of laser, fruit acid peeling, liver drugs and other ways. 1. Sunlight exposure: patients may be exposed to sunlight for a long time in their lives, resulting in localized melanin deposits and darkening of the corners of the mouth, which can be treated by laser, eliminating the pigment cells in the bottom layer of the skin and discharging them out of the body along with the body’s metabolism, which can effectively alleviate the darkening of the corners of the mouth. 2. Improper skin cleansing: patients may not do a good job of skin cleansing in a timely manner, resulting in the emergence of dark corners of the mouth, can be relieved through the way of fruit acid peeling, which can effectively remove the aging of the skin stratum corneum, but also deep cleaning of the skin, can be effective in relieving the symptoms of dark corners of the mouth. 3. Liver disease: If the patient suffers from liver disease, liver function is damaged, the melanin processing capacity is reduced, resulting in melanin deposition caused by the phenomenon of black mouth corners, can be relieved by taking hepatoprotective drugs, such as glutathione oral solution, glucuronide tablets. When the symptoms of darkening of the corners of the mouth, you should go to the hospital in a timely manner to identify the cause of the disease, under the guidance of the doctor, targeted treatment.