The vagina is the reproductive tract, the passage for menstruation, sexual intercourse, and the delivery of the fetus. The anus is the passage for the digestive organs, through which the remains of digested food are expelled. Both are innervated by the random muscles, which can be instructed by the brain to contract or relax. The difference between the two is that the vaginal mucosa has many folds and is clinically very stretchable, so that a full-term fetal head, with a biparietal diameter of 10 cm, can be delivered through the vagina. The anal canal is not as stretchy as the vagina. It is recommended to keep the vulva clean in daily life and also to eat spicy and acidic stimulating foods to reduce the stimulation of the anal mucosa.