It is normal for brown discharge to appear two days after menstruation. There are several main reasons for this: Firstly, it is considered to be caused by prolonged menstruation and incomplete shedding of endometrium, which can lead to brown discharge when the flow of menstruation is slow and the endometrium is not completely discharged after shedding. Secondly, it is considered to be caused by organic lesions, such as cervical cancer and cervical polyps. When the disease appears, it will also directly affect the discharge of menstrual blood and produce brown discharge, so it is recommended to go to the hospital for cervical cancer screening in time to determine whether there is a disease reaction. Thirdly, it is considered to be caused by uterine cold and weakness of qi and blood. When uterine cold appears, it will directly affect menstruation and prolong menstruation, which needs to be treated in time.