The purpose of the present Perspectives is to present a synopsis of the literature on bacterial "quorum sensing" as a background for the proposal that interference with this communication system offers potential targets for the design of novel antibiotic drugs. Quorum sensing is the recently discovered chemical communication system among bacteria (both Gram-positive and -negative). It is vital for intra- and interbacterial gene regulation and for keeping bacterial colonies ("biofilms") intact, allowing resident bacteria to assume specialized roles that contribute to enhanced survival of the group. There are several processes involved in quorum sensing that are familiar to pharmacologists; i.e., specific signaling molecules bind to and activate receptors that transduce the quorum-sensing signal into intracellular second messenger responses. We highlight herein the similarity between quorum-sensing communication to ligand-receptor interactions, suggesting that inhibitor drugs could be designed using current standard pharmacologic principles. Such drugs would have novel mechanisms of action and might therefore be more effective against antibiotic-resistant strains of bacteria.