Corner of the mouth melanin precipitation may be keratitis, primary hypoadrenocorticism, chronic liver disease, etc., can be treated by laser and other medical aesthetic treatment, follow the doctor’s instructions for oral hydrocortisone and other hormone drugs, reduced glutathione and other hepatoprotective drugs to help improve the treatment. 1. Keratitis: Keratitis often occurs in the corners of the mouth red, swollen, cracked, vesicles and other symptoms, repeated episodes can be caused by the corners of the mouth melanin precipitation occurs, hyperpigmentation of the serious can be prescribed laser treatment and other aesthetic methods to help improve the corners of the mouth blackening symptoms. 2. primary hypoadrenocorticism: it will interfere with the body’s melanin metabolism, thus causing generalized skin and mucous membrane hyperpigmentation, and then the corners of the mouth black and other symptoms, such patients can be prescribed to take hydrocortisone, cortisone and other hormonal drugs, to improve the corners of the mouth black symptoms. 3. Chronic liver disease: a variety of chronic liver disease (such as hepatitis B, cirrhosis, etc.) will cause the body melanin metabolism disorders, resulting in hepatic face, dark corners of the mouth and other facial melanosis phenomenon, such patients can follow the doctor’s instructions to take reduced glutathione, can deoxycholic acid and other hepatoprotective drugs to help improve liver function, and then alleviate the corners of the mouth black. If there is a black pigmentation of the corners of the mouth, it is recommended to go to the regular hospital in a timely manner, to clarify the cause of the disease, under the guidance of the doctor’s medication.