Black vaginal discharge is mainly due to bleeding from the reproductive organs, and the blood is discharged for a long time, so the discharge is black. The causes of bleeding are early pregnancy, slight bleeding due to embryo implantation, small amount of bleeding, and black-brown discharge due to long time of blood discharge. At the end of menstruation, the discharge of menstrual blood is very small and mixed with leukorrhea, and when it is discharged together, black discharge is formed, and in case of ectopic cervical columnar epithelium with cervicitis, there is localized blood oozing. Black discharge may also occur in cases of vaginitis, pelvic inflammatory disease, adnexitis, and endometritis. Tumors and cysts in the reproductive area can also cause black discharge, which is related to endocrine disorders and fluctuating levels of sex hormones in the body, such as missed contraceptive medication and decreased ovarian function during perimenopause.