If the menstrual cycle is relatively short, about 25-26 days, the causes of vaginal brown discharge about 4 days after clean menstruation are as follows: 1, if there is no abdominal pain and other special circumstances, mainly consider ovulatory bleeding, ovulatory bleeding 3-4 days can be clean, more than no discomfort, no need for treatment; 2, if this time the period is not normal, there is a delay in menstruation or low volume, consider abnormal pregnancy resulting in bleeding, such as pre-eclampsia or If there is brown vaginal discharge after 4 days of menstruation, contact bleeding is considered and cervical screening is needed to exclude cervical cancer and intraepithelial neoplasia of the cervix; 4. If the patient has abnormal coagulation function or tumor lesions of the cervix and ovaries, as well as polyp lesions, the patient needs to be diagnosed through gynecological internal examination, gynecological ultrasound, or even hysteroscopy.