Compounds having a broad range of antimicrobial activity generally have a structure including a steroid nucleus with a cationic, preferably polyamine, side chain (X) and an anionic side chain (Y). The invention is also directed to compounds of formula (III) preferably where the steroid ring nucleus is saturated; the steroid ring substituent Z5 is alpha -H; one Z7 is beta -H and the other is alpha -H or alpha -OH; both substituents Z12 are hydrogen; X' is a polyamine side chain of the formula -NH-(CH2)p-NH-(CH2)q-N(R )(R ) where p and q are each independently 3 or 4, and R and R are each independently hydrogen or methyl; R' is methyl; and Y' is (C1-C10)-alkyl substituted with a group such as -CO2H or -SO3H.