The physiological period is 3-7 days. If the menstrual volume is too little or too much, it is abnormal. The normal menstrual cycle is 23-37 days, with an average of 28-30 days, and the menstrual volume is about 50 mL. Of course, each person is different, and menstruation is controlled by the hypothalamus-pituitary-ovary axis. Usually, no treatment is needed. Pay attention to a reasonable diet, do not lose too much weight or exercise excessively, maintain a stable mood and stay up late as little as possible. With stable hormone levels, menstruation will be naturally safeguarded. Frequent disruption of the menstrual cycle for more than three consecutive months requires examination at a hospital and treatment under the guidance of a doctor.