BACKGROUND: Intradermal test is a useful diagnostic method for acute anaphylactoid or anaphylactic reactions induced by anesthetic drugs. We analyzed the responses of intradermal test for anesthetic drugs in patients who did not show anaphylactoid or anaphylactic reactions. METHODS: The authors performed intradermal test for anesthetic drugs (thiopental, midazolam, fentanyl, atracurium and vecuronium) in 224 adult patients one hour before induction of anesthesia. The responses were interpreted as measuring the size of wheal and flare. We also did history taking for past allergic history. RESULTS: There were no patient that showed positive reaction. The rate of false positive reaction for atracurium (12.5%) was significantly higher than other anesthetic drugs (p<0.05). And the rate of false positive reaction for atracurium in patients under the age of 40 (20%) was significantly higher than those above the age of 40 (3.8%) (p<0.05). But the difference of the rate of false positive reaction for atracurium between male (8%) and female (15.3%) was not significant statistically. The differences of the rates of false positive reaction for anesthetic drugs between past allergic history group and no past allergic history group were not statistically significant. CONCLUSIONS: In intradermal test for anesthetic drugs, the rate of false positive reaction for atracurium was significantly higher than thiopental, vecuronium, fentanyl and midazolam. Especially, it was significantly higher in patients under the age of 40. So in performing intradermal test to search for causative anesthetic drug, we have to consider the high rate of false positive reaction for atracurium.