Under normal circumstances after a woman’s cesarean section, the bad dew usually clears up in about 10 days, and the longest usually does not exceed half a month. If the patient keeps the presence of bad dew within a month after the cesarean section and then turns bright red after a month, this situation should be considered for the following possibilities: Firstly, the patient may catch up with the onset of menstruation. Some women have normal menstrual periods about a month after delivery. Second, we should consider the possibility that the patient has residuals in the uterine cavity, for example, the patient has placenta residuals, in which case we need to do gynecological ultrasound to make a clear diagnosis. Third, to consider the possibility of infection in the uterine cavity. Infection of the uterine cavity can cause the patient to appear vaginal bleeding for a long time, bleeding, but usually accompanied by abdominal pain or fever and other discomforts. Fourth, to consider the cesarean section incision healing or patients with scar diverticulum, need to do gynecological ultrasound to check.