Myristalkonium is used as spermicide in vaginal contraceptives. It has antiseptic properties also. Breastfeeding women might use it because it does not pass into maternal milk. Absorbed only on the surface of the walls of the vagina and then return to normal physiological droppings or eliminates simple washing with water. Adverse effects are: burning, itch, contact dermatitis. Any drug, introduced into the vagina, can inactivate the local spermicidal action of Myristalkonium.