A small amount of vaginal bleeding after coitus can be seen in the following situations: First, gynecological inflammation such as cervical erosion, cervicitis, cervical cysts, cervical polyps, a small amount of bleeding after coitus. Second, functional uterine bleeding, and the body’s hormone level disorders have a certain relationship. Third, vaginal diseases, such as repeated vaginitis patients, according to the medical history, as well as women’s physiological cycle and auxiliary examination can find a clear cause. Fourth, the female body is extremely weak, resistance to decline or in the ovulation period, pre-menstrual period are prone to small amounts of vaginal bleeding after intercourse. The causes of small amounts of vaginal bleeding at different times are different, and require a further comprehensive history, symptoms and signs to diagnose, before the cause is identified, it is recommended not to have intercourse, so as not to aggravate the condition.