Terbinafine, a synthetic antifungal of allylamine class, has fungicidal activity against dermatophytes, moulds and certain dimorphic fungi and fungistatic activity against Candida albicans. Following oral administration the terbinafine is absorbed rapidly (>70%) and reaches within 2 hours the peak plasma concentration. The drug is highly lipophilic and keratophilic and is highly bound to plasma protein (>90%) with a bioavailability of 70% to 80%. The drug is rapidly delivered and it is present in the stratum corneum, sebum, nails and hair for months after stopping the medication. The drug has been proven to be the choice treatment in the therapy of onychomycosis as it is very effective, well tolerated and has a relatively low potential for drug interactions. The pharmacologic and pharmacokinetic properties of terbinafine give strong support to the possibility that the pulse therapy may be equally effective in onychomycoses, possibly reducing medication costs and drug exposure. Several therapeutic patterns have been proposed: weekly intermittent terbinafine (500 mg/d for 1 week each month for 4 months), or single-dose terbinafine (1000 mg per month for 4 months). Use of topical terbinafine 1% may be practical where the tinea involvement is not extensive or chronic. Recently, the terbinafine is available in a novel topical solution (film-forming solution--FFS) effective in the treatment of tinea pedis (athlete's foot).