Gray hair may be caused by physiological phenomena or by pathological causes such as albinism and vitiligo. It can be darkened by drugs and hair coloring. 1. physiological phenomenon: the elderly hair gray or white, is due to the melanocytes in the tyrosinase activity progressive loss of the hair shaft pigmentation caused by the disappearance. This is a physiological phenomenon, which can be solved by coloring the hair black, but this can only temporarily relieve the phenomenon of gray hair. 2. Albinism: a group of congenital skin, hair and eye partial or complete loss of pigment hereditary disease. In the case of a complete loss of pigmentation, the hair color can be white for life. It is also possible to turn white hair into black hair by means of hair coloring. 3. Vitiligo: It is a common acquired pigment loss skin and mucous membrane disease, clinically manifested as white spots or (and) white hair, can occur in all parts of the body. Oral or intramuscular injection of glucocorticoids can be chosen to stabilize the progressive vitiligo as soon as possible. Commonly used drugs include prednisone and compound betamethasone. In addition, it is recommended that patients who want to turn gray hair black, go to the hospital, clear the cause of the disease to follow the doctor’s instructions for drug treatment, to avoid delaying the condition.