Contraception is one of the keystones of reproductive health. The availability of effective contraception has helped to change dramatically the structure of the world's population during the last 50 years, through a demographic transition involving lower fertility rates and longer survival. As the transition evolves more slowly in developing countries, different effects on population structures contribute to civil strains. Oral contraception (OC) is an extremely effective method of contraception that also confers health benefits beyond pregnancy prevention. Notable effects on the reproductive system include relief from troublesome symptoms associated with menstruation such as heavy periods, painful periods and irregular bleeding. Many women also have improvement in acne and hirsutism. Moreover, OCs may be used to treat menorrhagia or symptomatic endometriosis. Use of OCs is associated with a long lasting reduction in the risk of developing cancer of the ovary and the endometrium. The effects on benign breast disease (BBD), bone health and colon cancer are less clear and merit further investigation.