Superficial mycosis such as Tinea pedis affects between 10 and 15% of the population and is amongst the top ten reasons for visiting the doctor in Mexico. The vegetal species Solanum chrysotrichum has been, for many years, widely used in Mexican traditional medicine for the treatment of fungal foot infections. This paper illustrates the results of a controlled and randomized, double-blind clinical trial, which compared the therapeutic effect and the tolerability of a standardized phytodrug from S. chrysotrichum (experimental group) with 2% ketoconazole (control group), applied externally (4 weeks) to 101 patients diagnosed with Tinea pedis. After the treatment, the results showed a clinical effectiveness (> or = 75% improvement of signs and symptoms) of 96.08 % for the group treated with the S. chrysotrichum extract and 91.67% for the ketoconazole group (chi 2, p > 0.38); the mycologic effectiveness (direct examination and negative culture) was 78.43 % and 77.78%, respectively (chi 2, p > 0.94); whilst the tolerability was 100% for both treatments. The therapeutic successes (clinical and mycologic effectiveness plus tolerability) was 74.51% with the experimental treatment and 69.44% with the control (chi 2, p > 0.60). These results support the safety and effectiveness of Solanum chrysotrichum standardized phytodrug for the treatment of Tinea pedis.