Abstract: Pharmaceutical compositions comprising a combination of a polymeric biguanide and a spermicidal surfactant, useful for contraceptive purposes, for their spermicidal or sperm-immobilizing effect, and contraceptive methods and devices using them.The polymeric biguanide is preferably a compound as described in U.K. Patent Specification No. 702,268 or a bisbiguanide as described in U.K. Patent Specification No. 705,838 or 1,095,902, but especially chlorhexidine. The spermicidal surfactant may be derived from ethylene oxide, preferably a condensate of nonylphenol and ethylene oxide, and especially with 9 to 11 molecular proportions thereof.To avoid short-lived activity, the compositions are preferably made substantially free from anions (notably halide ions and especially chloride ions) which cause deactivation, apparently by reducing the solubility of the active ingredients.