Hair graying may be a normal physiological phenomenon, or it may be caused by excessive stress, vitiligo and other reasons. 1. physiological phenomenon: with age and aging of the human body, the gradual loss of tyrosinase activity in the hair melanocytes, resulting in a decrease in melanin, thus appearing in the case of hair whitening, which is a normal physiological phenomenon, no need to worry about too much, such as the image of the need for the patient, you can dye the hair to improve the appearance. 2. mental stress: when the patient long-term emotional tension, emotional fluctuations, mental stress or long time worry, sadness, etc., leading to metabolic abnormalities in the body, may also lead to rapid hair white. 3. Vitiligo: Vitiligo is a common acquired pigment loss skin and mucous membrane disease, mainly manifested as white spots, white hair and other symptoms, the patient appeared hair white, may be caused by vitiligo. It is recommended that the patient timely medical examination, clear causes for targeted treatment, in life to strengthen nutritional supplements, reasonable diet, pay attention to personal hygiene, keep hair clean and fresh.