Etiology: Unknown. It may be related to the following factors: 1. It occurs in the third to fifth month of pregnancy and recurs in the next pregnancy, called pregnancy melasma. 2. Most often seen in people with a history of oral contraceptives, phenytoin sodium and other drugs. 3.It is also seen in chronic diseases such as tuberculosis, cancer, chronic alcoholism, chronic liver disease, malnutrition and anemia, mental and emotional abnormalities, endocrine disorders, etc. Features: light brown or dark brown patches with clear boundaries, symmetrically distributed, usually on the cheek, forehead, nose and upper lip, often aggravated in summer or in case of poor sleep and mental and emotional abnormalities, and reduced in winter. Treatment: 1. External medicine: 3% hydrokun, azelaic acid, tretinoin, arbutin or Chinese herbal medicine and other melanin inhibitors can reduce the symptoms. 2. Internal herbal medicine: Liu Wei Di Huang Wan, Xiao Yao Wan, Run Yi Rong Capsule, Blemish Removal and Menstrual Regulation Capsule and Peach Red Four Objects Soup Plus have certain effect. 3.Other oral medicine: tranexamic acid (tosamer) 0.5/time, 2 times/day, 2 months/course. 4.Injectable drugs: vitamin C 4.0 IV, once every other day, 1~2 months/course. 5, laser treatment: commonly used Q-modulated-Nd: YAG laser 1064nm wavelength, pulsed dye laser, photon or fractional laser treatment, but can not completely prevent recurrence. Efficacy: The cause of the disease is unknown and related to a variety of factors, the efficacy is slow, and there is no reliable cure. Most patients can be reduced to varying degrees after 3 to 6 months of comprehensive treatment.