Pirtenidine is the antimicrobial agent. Pirtenidine was found to be highly efficacious against oral plaque-forming microorganisms. Adherence of Candida spp. to buccal epithelial cells in vitro was significantly reduced after both short- and long-term periods of yeast exposure to sub-inhibitory concentrations of pirtenidine. The drug was shown to cause extensive leakage of cytoplasmic contents from the Candida albicans cells which was correlated with morphological and ultrastructural changes in the yeast. Pirtenidine affects the lipids and sterol composition of C. albicans.