Skin infections are common diseases in developing countries, of which dermatophytoses are of particular concern in the tropics, especially in infants. Through ethnobotanical surveys and literature review 100 plants were detected as being used in Guatemala for the treatment of dermatophytoses. Of these, 44 plants were screened for in vitro activity against the most common dermatophytes (Epidermophyton floccosum, Microsporum canis, Microsporum gypseum, Trichophyton mentagrophytes and Trichophyton rubrum). Results showed that aqueous extracts from 22 of the plants tested inhibit one or more of the dermatophytes. The most commonly inhibited dermatophytes were E. floccosum (43.2%), T. rubrum (36.0%), and T. mentagrophytes (31.8%); the less inhibited were M. canis (22.7%) and M. gypseum (24.0%). Plants of American origin which exhibited anti-dermatophyte activity were: Byrsonima crassifolia, Cassia grandis, Cassia occidentalis, Diphysa carthagenensis, Gliricidia sepium, Piscidia piscipula, Sambucus mexicana, Smilax regelii, Solanum americanum and Solanum nigrescens. Fungicidal and fungistatic activities as well as the minimal inhibitory concentration were demonstrated. These results provide a scientific basis for the use of these plants for the treatment of dermatophyte infections in man.