There are more reasons for people to grow gray hair, which may be related to aging, life factors, hereditary diseases, acquired diseases and so on. 1. Ageing: If the patient is older, it may be due to aging of the human body and reduced function of melanocytes. 2. Life factors: If the patient is picky about food, partiality or excessive dieting, it may lead to a lack of folic acid, vitamin B12, zinc and other elements, all of which may lead to hair whitening. In addition, if the emotional tension, stress, long-term sun exposure, may grow gray hair. 3. Hereditary diseases: for example, patients have albinism, which can lead to whitening of the whole body skin and hair on the body, and reduced vision. In addition, mottled disease, tuberous sclerosis may also lead to gray hair. 4. Acquired diseases: If the patient has hyperthyroidism, tuberculosis, vitiligo, Parkinson’s disease and other acquired diseases, they may cause white hair. Because of the cause is more, patients can best timely consultation, clear cause, actively cooperate with the doctor treatment.