The black color of a ten year old girl’s menstrual period is often considered to be related to low menstrual flow and poor menstrual blood discharge. 1. low menstrual volume: for ten-year-old girls, the gonadal axis function is not yet fully mature, so the girl will have irregular ovulation, which may lead to low levels of estrogen and progesterone in the body, which leads to a low menstrual volume of black color. 2. Poor discharge of menstrual blood: if the girl bed rest or menstrual period of abdominal cold, etc., may lead to poor discharge of menstrual blood, and then in the vagina to stay in contact with the air after the oxidation reaction and lead to black color. For ten-year-old girls, to pay attention to abdominal warmth when menstruation, take brown sugar water if necessary, do not do strenuous exercise, pay attention to personal hygiene during menstruation, if the color of menstruation continues to be black, it is recommended that they go to a regular hospital gynecology consultation, clear cause of the cause of the disease in the guidance of the doctor to actively treat.