The new imadozolyl derivative 1-(p, alpha-diphenyl-benzyl)imidazole (bifonazole, Bay h 4502, Mycospor) shows in vitro the broad spectrum of activity characteristic of azole antimycotics. The intensity of activity under conventional test conditions is equivalent to that of clotrimazole. Further, concentrations of less than or equal to 5 micrograms/ml bifonazole have a fungicidal effect on dermatophytes, and a MIC value of less than or equal to 0.25 micrograms/ml has a maximal effect on Torulopsis glabrata. In ng concentrations bifonazole is effective on proliferating dermatophytes and pseudomycelia of Candida albicans. The resistance situation regarding bifonazole is favourable--as is typical of azole antimycotics. In animal experiments, topical application of concentrations of between 0.05 and 1% bifonazole as a cream or solution are extremely effective on guinea-pig trichophytosis. This is attributed to the therapeutically achievable fungicidal effect on dermatophytes and the long period of time the substance is retained in the skin. The sum of the experimental properties of bifonazole make it possible to recommend the active drug to be applied, once every 24 h, as a 1% cream or solution and the duration of therapy for these indications being reduced to 2-3 weeks.