The reasons for half a month of menstruation are considered to be gynecological diseases, endocrine disorders and the influence of diet. Common gynecological diseases, such as endometritis, endometrial polyps, uterine fibroids, etc., can easily lead to incomplete shedding of the endometrium during menstruation and cause prolonged periods, so you can go to the hospital for ultrasound examination and then treat the symptoms. Once the endocrine disorder occurs, it will also lead to irregular menstruation. Do a female hormone six check, if there are abnormalities, you can use hormonal drugs to regulate under the guidance of the doctor. There is also a certain relationship with diet, during the period must pay attention to avoid eating some stimulating food, such as chili, hot pot, barbecue, do not eat frozen food, so as not to stimulate the uterus contraction, causing a long period is not clean.