Twenty human volunteers were entered into a study to investigate the pharmacokinetics of terbinafine 1% cream. Subjects were randomized to receive terbinafine 1% cream applied to the back on 1 day, or on 3, 5 or 7 consecutive days. Up to five sequential skin surface biopsies were taken at a site on the upper back at various time-points both during treatment, and following cessation of treatment. Terbinafine levels in these biopsies were analysed using HPLC. The study showed that increasing the number of applications from one to seven did not significantly increase the peak concentration (Cmax) in the stratum corneum. It did, however, increase the total amount of terbinafine found in the stratum corneum, resulting in terbinafine being detected for longer periods after cessation of therapy. Treatment for 7 days resulted in terbinafine still being detectable 7 days after cessation of therapy, when the terbinafine concentration was significantly higher than the known cidal concentrations for the common causative organisms of superficial dermatomycoses. This study indicates a significant potential for short-duration treatment with terbinafine (Lamisil) 1% cream in superficial dermatomycoses.