By plotting profiles of reported adverse reactions related to the skin, a fairly characteristic picture for each drug emerges. Analysis of these profiles provides useful data on the relative incidence of a particular adverse reaction due to individual drugs. Except for the long-acting sulfonamides, there are remarkable few differences between various chemotherapeutic agents in the incidence figures for erythema exsudativum multiforme-like reactions. Analysis of the data of the International Drug Monitoring Program might provide a new method for delineating the significance of drugs as aetiological factors in erythema multiforme, the Stevens-Johnson syndrome and toxic epidermal necrolysis