Compounds with multiple biguanide groups such as chlorhexidine, alexidine, and PHMB are used as topical antimicrobials in a variety of settings. We have synthesized a series of small molecules with guanide, biguanide, and arylguanide functional groups that have comparable broad spectrum antibacterial activity, but lower cytotoxicity towards mammalian cells. We are investigating their mechanism of action and further optimizing their structures.