A 26 year old patient developed a fixed drug eruption located on his hands, inguinal and gluteal areas following oral treatment of onychomycosis with terbinafine. The rash showed the characteristic distribution of the "baboon-syndrome", so-named because of the red perianal region of the baboon. Although epicutaneous testing revealed no positive reaction, the rash could be induced in identical sites by oral administration of terbinafine. As the underlying pathomechanism for the "baboon-syndrome" a systemically induced allergic contact dermatitis has been suggested. In addition to the described substances, e.g. mercury, amoxicillin, ampicillin, heparin and nickel, this is the first report of "baboon syndrome" induced by terbinafine.