The vagina is part of the female reproductive system. It is a tubular, mucosal duct that connects the uterus to the external organs of the female reproductive system. It is on average between 7 and 12 centimetres long. The vagina has a natural vaginal flora, which is essential for its balance. The vaginal flora, which consists mainly of Döderlein bacilli, provides competitive protection against pathogenic microorganisms.

The vagina has important functions in reproduction. It receives the penis and sperm during sexual intercourse. As a highly erogenous organ, it is also responsible, together with the clitoris, for the sensations experienced during intercourse. In contrast, the cervix, which has very few nerve endings, is not involved in this sensation. The vagina facilitates the access of spermatozoa to the uterus. The vagina also plays an important role in reproduction, as it must allow the passage of the newborn child. The thin walls of the vagina have many folds and thus allow the necessary expansion during childbirth.