The antimicrobial activity of 5-chloro-2(2,4-dichlorophenoxy) phenol (triclosan, one of the active ingredients of Logamel®, Ciba-Geigy) was compared in vitro with that of other antimicrobials exclusively or occasionally used as topical agents in dermatology: hexachlorophene, clioquinol, chlorquinaldol. gentamicin, neomycin, nystatin, econazole, clotrimazole and salicylic acid. Upon determination of the MICs for 53 strains of aerobic and anaerobic bacteria, yeasts and fungi, triclosan was found to display a high degree of activity against most of the test organisms and to have the broadest spectrum of chemotherapeutically significant antimicrobial activity of the substances tested.