The most common cause of yellow water after menstruation is vaginal inflammation. You can have a routine laboratory test of the white belt to find out whether there is pathogenic infection and then decide whether treatment is needed based on the results. It is also necessary to find out if there is cancer in the cervix, endometrium and fallopian tubes, all of which require ultrasound and screening for cervical cancer. If the yellow water is flowing out on its own without consciousness, it is also necessary to rule out whether the urine flow is caused by vesicovaginal fistula. If this is the case, prompt repair surgery is recommended.