Dark red discharge on the panties should be bleeding, but the amount of blood is not very large, so the color is not particularly red, and most of it is abnormal uterine bleeding. This condition is commonly seen in cases of hormonal abnormalities, pregnancy bleeding, medication bleeding, bleeding due to gynecological diseases, etc.: I. Hormonal abnormalities 1. Intermenstrual bleeding: If the bleeding is between two periods, it may be ovulatory bleeding. Ovulatory bleeding is a breakthrough bleeding caused by the endometrium when the estrogen level is low and does not reach a certain threshold. Occasionally, it can be observed first, and if it often occurs, it needs to be supplemented with estrogen, and can also be treated with contraceptives as prescribed by the doctor. 2. Bleeding before and after menstruation: If there is this abnormal coffee-colored or dark red discharge before menstruation, or if the menstruation lasts for a long time and then slowly becomes dark red, or if the dark red discharge appears again one or two days after the menstruation is clean, it may be a bad luteal function. If it appears before menstruation, it is luteinizing insufficiency, while after menstruation, it is mostly luteinizing atrophy insufficiency. If it occurs once in a while, you can also observe it first. If it occurs frequently, you need to treat it with progesterone. It is also possible to use birth control pills because they contain estrogen and progesterone. Second, pregnancy bleeding: if a woman has sex, it is necessary to exclude whether there is pregnancy or not. Some women who are pregnant will have pre-eclampsia miscarriage or biochemical pregnancy, etc., which may have dark red bleeding. Third, drug bleeding: if a woman takes emergency contraceptives, abnormal vaginal bleeding may also occur after stopping the pills. Dark red discharge will appear on the panties; iv. Bleeding due to gynecological diseases: Patients with cervical lesions or inflammation of the cervical canal, for example, will have dark red discharge after intercourse. In addition, if vaginal inflammation persists without remission, inflammatory stimulation can also trigger the situation of dark red discharge on the underwear. Therefore, it is best to go to the hospital for a checkup to find out the cause of the dark red discharge and then to deal with it in a targeted manner.