Vaginal bleeding five days before menstruation may be the onset of menstruation, which is a normal phenomenon, but vaginal bleeding can also be seen in certain diseases, such as cervicitis, luteal insufficiency and so on. Normal female menstruation has a certain cycle, the cycle is usually 21~35 days, the period is usually 2~8 days, regulated by the female endocrine system hormones, daily life, such as the environment, fatigue, etc. may lead to changes in the menstrual cycle. However, vaginal bleeding should be excluded from related diseases, such as cervicitis, which can be manifested as vaginal bleeding after gynecological examination or sexual intercourse; luteal insufficiency, which can be manifested as a shortened menstrual cycle or difficulty in conceiving, and so on. It is necessary to determine whether the vaginal bleeding is normal menstrual cycle according to the causative factors, the amount and duration of bleeding, etc. If there are obvious causative factors or obvious differences from normal menstruation, it is necessary to consult a doctor in time to clarify the cause of bleeding and then treat the symptoms.