The present invention relates to a contraceptive composition including an effective amount of a dendrimer compound including one or more naphthyl disulphonic acid surface groups, or a pharmaceutically acceptable salt or solvate of the dendrimer compound; and a pharmaceutically acceptable carrier, excipient and/or diluent therefor. The contraceptive composition may also exhibit antimicrobial activity. The invention also relates to a method of selectively reducing or preventing conception in a female animal, including a human, which method includes administering to the animal an effective amount of a contraceptive composition which composition includes an effective amount of a dendrimer compound including one or more naphthyl disulphonic acid surface groups, or a pharmaceutically acceptable salt or solvate of the dendrimer compound; and a pharmaceutically acceptable carrier, excipient and/or diluent therefor.