The in vitro activity of 2,2´-dipyridyl, an ironchelator, against clinical isolates of Trichomonas vaginalis, Candida albicans, and Gardnerella vaginalis was evaluated and compared with those of four other vaginal suppositories, ornidazole, clotrimazole, povidone-iodine, and Cenacert^ (Methylbenzethonium Chloride mixed with 9-aminoacrydine undecylenate and hydrochloric acid N-myristyl-3-hydroxy butyl amine). The 2,2´-dipyridyl killed T. vaginalis and G. vaginalis at concentrations of 410㎍/ml and 205㎍/ml, respectively, however, this agent was less active against C. albicans (80% of which was inhibited at 410㎍/ml). The inhibition of these three pathogens by 2,2´-dipyridyl was similar to clotrimazole. In addition, the effect of 2,2´-dipyridyl on the ultrastructure of T. vaginalis, C. albicans, and G. vaginalis was examined. Transmission electron microscopy indicated that 2,2´-dipyridyl induced modifications of the cellular contents and cell envelope concomitant with the degradation of the three pathogens. These results suggest that 2,2´-dipyridyl has an inhibitory effect on C. albicans and G. vaginalis, as well as T. vaginalis.