Normal people will lose hair every day, within 100 roots are considered normal: a. Because hair has 3 stages: growth period, resting period and resting period, some hair may be in the growth period, some hair may be in the resting period, the hair in the resting period is easy to fall out, if the daily within 70-100 roots are considered normal, this is the physiological hair loss, hair loss. Second, may be androgenic alopecia, androgenic alopecia male is more common, mainly related to genetics, because the body 5α-reductase inhibitors elevated hair loss is also known as male off, you can use drugs such as finasteride oral or minoxidil topical treatment. Third, postpartum hair loss, after the birth of a child, some women due to fatigue or mental factors can cause hair loss, postpartum hair loss can be treated with oral medication and attention to rest. Four, spot baldness, mental factors or autoimmune factors lead to hair loss, often a sudden appearance of patchy hair loss.