Chlorhexidine has been used for the past 35 years in the treatment of the two primary diseases of dentistry with varying degrees of success. The purpose of this paper is to review the literature for both the caries reduction potential and the microbiologic reduction of the pathogens associated with dental caries. The literature remains mixed on the success of chlorhexidine for the reduction of dental caries. Its performance as an antimicrobial against Streptococcus mutans is more consistent and favorable.