The vagina is about 7-12 cm deep and is the organ of sexual intercourse, as well as the channel for the discharge of menstrual blood and the delivery of the fetus. The vagina is located in the lower central part of the pelvis and is wide at the top and narrow at the bottom, with the upper end connected to the cervix. The vagina is very stretchable and is a flexible muscular tissue with a wall of mucous membrane, muscular and fibrous tissue membranes, with many transverse wrinkles and a rich plexus of veins that bleed easily after injury. Under normal circumstances, the vagina has a certain self-cleaning ability and certain microorganisms can live in the vagina, but in general, it does not develop, but when the immunity of the body decreases or the pH of the vagina changes, it can easily cause vaginitis and symptoms such as increased leucorrhea, yellowing and odor.