Methods of reducing the risk of transmission of a sexually transmitted pathogen by contacting the pathogen or cells susceptible to infection by the pathogen with a .beta.-cyclodextrin are provided. Methods for reducing the risk of transmission of a sexually transmitted pathogen to or from a subject by contacting the pathogen or cells susceptible to the pathogen in the subject with a pharmaceutical composition containing a .beta.-cyclodextrin also are provided. Accordingly, pharmaceutical compositions, which include 1) a .beta.-cyclodextrin, which is in an amount that blocks passage of the pathogen through lipid rafts in the membrane of a cell susceptible to the pathogen, and 2) a contraceptive, an agent for treating a sexually transmitted disease, a lubricant, or a combination thereof, are provided, as are composition formulated from a solid substrate that contains an amount of .beta.-cyclodextrin useful for reducing the risk of transmission of a sexually transmitted pathogen.