Oral terbinafine is widely used in the treatment of superficial dermatomycoses as well as subcutaneous and systemic mycoses. It is also useful in treating tinea capitis, although for Microsporum canis and some ectothrix organisms, the effectiveness of the drug may be less than for some endothrix infections. In this study, we undertook a double-blind randomized trial comparing standard and double doses of terbinafine given in a pulsed protocol (1 week on, 3 weeks off) in treating Microsporum spp. tinea capitis in 42 individuals. We found that pulsed terbinafine at a higher dose did not improve treatment efficacy. However, our data clearly demonstrated that the duration of treatment is an important factor in determining clinical outcome and cure. Two pulses of standard dose terbinafine were found to be sufficient for treating most cases of Microsporum spp. tinea capitis, although additional treatment (a third pulse) may be needed if clinical improvement is not evident at 8 weeks after initiating therapy.