A double-blind study with terbinafine was performed in 39 patients with dermatophyte infection, between 1987 and 1989, to compare the safety and efficacy of two dosage schedules of 125 mg twice daily versus 250 mg once daily. Mycologic assessments were negative by microscopic examination and Sabouraud's culture in 59% and 100% of patients in the first and the fourth weeks of treatment, respectively. There was no statistically significant difference between the two groups of patients receiving 125 mg b.i.d. and 250 mg q.d. with respect to the safety and efficacy of the treatment; however, the differences between the sums of clinical scores before and after the treatment were statistically significant. There were no adverse effects, and the drug was well tolerated.