The present invention is directed to methods of inhibiting STDs by topically administering suramin or a derivative thereof to actual or potential sites of infection, and methods of preventing pregnancy by topically applying suramin or a derivative thereof intravaginally. Suramin compositions that include an antimicrobial agent and/or a sperm-function inhibitor are also provided and may advantageously be used in the methods of the invention. A method of simultaneously inhibiting STDs and preventing pregnancy is also provided. Devices impregnated or coated with the topical suramin compositions are further disclosed and may be used to apply the compositions described herein.