Tolciclate [O-(1,2,3,4-tetrahydro-1,4-methanonaphthalen-6-yl)-m,N-dimethylthiocarbanilate] is an antimycotic agent with specific activity on dermatophytes. In vitro it is as active as tolnaftate, but shows greater liposolubility, which might be important for in vivo activity. When applied topically for 10 days to guinea pigs infected acutely with Trichophyton mentagrophytes (synonymous with T. asteroides), it is about three times more active than tolnaftate. Inhibition by tolciclate of sterol synthesis through blocking the step of squalene epoxidation in a fungal sterol biosynthetic pathway may be primarily involved in the antifungal action of the drug.