Menstruation is the exfoliative bleeding of the endometrium that accompanies the ovarian cycle. The appearance of regular menstruation is a sign of mature reproductive function. The usual menstrual cycle is about 28+-7 days. The volume is about 20-60 ml. More than 80 ml is considered excessive menstruation. Normal menstrual blood is not clotted and occasionally has small blood clots. There are many causes of abnormal uterine bleeding, go first to look for organic lesions and then to look for the endocrine system. The presence of abnormal menstruation in adolescent and perimenopausal females should be taken seriously. With the prevalence and high incidence of diabetes, obesity, and hypertensive diseases, the incidence of malignant diseases in the endometrium is increasing year by year. It is also important to pay attention to the health of older women. Among them, abnormal uterine bleeding, especially after menopause, should be noted and timely consultation is necessary.