The clinical efficacy of etonam (R 10 100) in the treatment of chronic athlete’s foot was investigated in a simple trial, a single-blind and a double-blind study embracing 161 male patients. Treatment comprised twice daily topical medication with 2 % powder or lotion as appropriate, for a minimum of 28 days. Severity of the lesions was assessed weekly and mycological investigations were made by microscopical examination and culture of scrapings.In all three trials dermatophyte-infected lesions were greatly improved after etonam treatment (significant at the 0.1 % level) and mycologically positive lesions markedly decreased (significant at the 5% level). No side-efiects were ever observed.Trichophyton mentagrophytes was isolated on 42 occasions before treatment, T. rubrum on 9, T. interdigitale on 5 and Epidermophyton floccosum on 2. No dermatophytes were observed after etonam treatment, though yeast cells were isolated in several cases, and those lesions containing yeasts but not dermatophytes were not alleviated by etonam treatment. © 1969 S. Karger AG, Basel.