There are various causes of hair loss, first of all, we need to clarify the cause of the disease, mainly including congenital factors, infections, systemic diseases, endocrine disorders, neuropsychiatric factors and so on. Afterwards, according to the cause of the disease, choose finasteride, ketoconazole and other drugs for treatment. 1. hair loss caused by congenital factors, such as dysplasia, congenital alopecia, etc., can not be treated by drugs. 2. hair loss caused by fungal infections can be treated with drugs such as ketoconazole and miconazole. 3. hair loss caused by systemic diseases, such as anemia, malnutrition, etc., need to clarify the type of anemia, according to the type of anemia supplement iron, folic acid, vitamin B12, etc., and supplemental nutrients. 4. Hair loss caused by endocrine disorders, such as hypothyroidism, androgenetic alopecia, etc., can be treated with drugs such as levothyroxine, finasteride and minoxidil. The use of drugs should be under the guidance of medical professionals to avoid adverse reactions.