Most girls menstruate between the ages of 13 and 15, but due to individual differences, the time of menstruation varies, as long as the menstruation occurs after the age of 9 and before the age of 18, it is a normal phenomenon. When a girl is menstruating, she should pay attention to the following matters: firstly, she should keep warm during her menstruation period. The second is to change sanitary napkins regularly during menstruation. The third is not to do strenuous exercise during menstruation, but to rest appropriately. The fourth is to pay attention to the diet during menstruation, do not eat frozen food, do not drink cold drinks, and do not eat cold food, such as watermelon, winter melon, barley, do not eat during menstruation.