If your period does not clear in 20 days, you should pay high attention to the clinical situation, it may be due to inflammation of the endometrium, endometrial polyps, submucosal fibroids or endometrial lesions, such as cancer of the endometrium, which may lead to incomplete menstruation. To understand the condition of the cervix and vagina and the pelvic cavity; 3. To do HCG test to rule out the possibility of pregnancy; 4. To do ultrasound test to understand clinically whether there are small tumors in the pelvic cavity and whether there is abnormal hyperplasia in the endometrium, and if necessary, to do diagnostic scraping. The final clinical diagnosis is based on pathology, to understand the causes of menstruation twenty days is still not clean, and then give treatment, this is in the clinical menstruation twenty days is not clean may appear in the cause.