The prevention of caries and gingivitis is mainly based upon modalities aiming to reduce supra- and subgingival dental plaque. Certain antibacterial agents may compensate for non-adequately self-performed mechanical plaque removal. While such prophylactic agents exhibit an antibacterial effect against oral microorganisms, the new agent delmopinol possesses the property of inhibiting the adhesion of oral microorganisms to the tooth surface. In numerous studies, delmopinol showed a plaque inhibitory potential. However, due to the lower efficacy and side effects similar to those of chlorhexidine, at present, delmopinol cannot be considered as an alternative to chlorhexidine. A long-term utilization of delmopinol in addition to the regular mechanical plaque control might be possible. For the time being there is a lack of studies comparing the efficacy of delmopinol to that of other antibacterial substances such as amine fluoride/stannous fluoride, triclosan/copolymer or cetylpyridinium chloride.