Background: Although drug eruption refers to a common dermatologieal condition, there are numerous setbacks in the diagnosis. In addition there are no annual average prevalence rates of drug eruptions according to time sequence in Korea. Objective : This study attempts to detme the clinical features and causative drugs of drug eruptions, the diagnostic value of various skin tests and to evaluate the dome,stic annual average prevalence rate of drug eruptions according to time sequence. Method: 270 patients with drug eruptions were reviewed clinically. In 103 patients, intradennal, patch and scratch-patch tests were performed using suspected drugs. The annual average prevalence rate of drug eruptions was calculated from 10 different general hositals in Korea. Result: Exanthematous eruptions(49.3), fixed drug eruptions(30.1), and urticaria(10.0%) were the common types of drug eruptions. The common causative agents were antibiotics/antimicrobials, antipyretics(NSAIDs, and CNS depressants. 52 patients out of 103 had positive results after at least one skin test with suspected drugs. Conclusion : In our study, we were ahle to obtain somewhat meaningful results basnl on data from the combination of various skin tests. As a result, physicians need to prescrible drugs with care. (Korean J Dermatol 1998;36(5) 887-896)