Melasma, also known as liver spots, is a common hyperpigmented skin disease occurring on the face, which can develop in both men and women, but is mostly seen in middle-aged women. The lesions are pale brown, coffee-colored or dark black patches with different sizes and irregular shapes. The surface is smooth without scaling and inflammation, and there are no self-perceived symptoms. They often appear symmetrically on both cheeks in a butterfly shape, and can also be seen on cheekbones, forehead, eyebrows and around the mouth, with individual patients spreading to the whole face. Some patients have increased skin pigmentation in the areola, external genitalia, armpits and groin. Etiology and pathogenesis of chloasma 1, physiological reaction: Pregnant women develop the disease in 3~5 months of pregnancy, and it gradually disappears after delivery, but it can still develop after re-pregnancy, which may be related to the imbalance of progesterone and estrogen in the body. 2.Symptomatic reaction: It can be seen in patients with dysmenorrhea, irregular menstruation, chronic pelvic inflammatory disease, liver cirrhosis, chronic adrenocortical insufficiency, chronic ethanol poisoning, tuberculosis, chronic bronchitis in the elderly, bronchial dilatation, tumor, etc. 3, drug factors: oral contraceptives cause the most, generally occurring after 1 to 20 months of oral intake, accounting for about 20%. It has been proved that it is due to the combined effect of estrogen and progestin. 4, cosmetic factors: with the widespread use of cosmetics, cosmetics caused by pigmentation is increasing, cosmetic dermatitis often left pigmentation after subsiding. 5, nutritional factors: some people due to the lack of vitamin A, vitamin C, vitamin E, niacin, zinc or certain amino acids, can also make the disease occur or develop, after giving supplementation can get significantly better. 6, other factors: such as thermal stimulation. Topical drugs, mental depression, often stay up late, excessive fatigue and other factors can also contribute to the development of the disease.