When a child has her first menstrual period, the mother should teach her child about physiology and life. 1. Physiology: Mothers should teach their children about physiology when a girl has her first period. Menstruation is a normal physiological phenomenon that occurs every month. When the lining of the uterus peels off in response to fluctuating hormone levels in the body, menstruation occurs and there is no need to be afraid. 2. Life: Girls should be told that women are weaker and have lower immunity during menstruation, so they should pay attention to their diet during menstruation, eat less cold, spicy and stimulating food, pay attention to keeping warm, avoid strenuous exercise during menstruation, get more rest, and avoid exertion. Girls should be taught how to use sanitary napkins and should pay attention to vulvar hygiene and change sanitary napkins frequently. If the girl has symptoms of dysmenorrhea, the girl should be taken to the doctor immediately and the pain should be alleviated by keeping warm and taking oral painkillers.