BACKGROUND/AIMS: Cimetropium bromide has been used widely as a premedication for endoscopy; however, there are no subjective data pertaining to the effects of cimetropum bromide as a premedication. Thus, the current study was undertaken to compare the effects of cimetropum bromide with placebo as a premedication for esophagogastroduodenoscopy (EGD). METHODS: Two hundred ninety-nine consecutive outpatients who had undergone EGD were enrolled in this study. Thirty minutes before EGD, the patients were randomly given an intramuscular injection of cimetropium bromide (5 mg) or saline using a placebo-controlled, double-blind, randomized technique. Immediately after EGD, all the patients and endoscopists were requested to fill out the questionnaire form. RESULTS: One-hundred patients were injected with cimetropium bromide and 150 patients were injected with placebo. There was no statistically significant difference in the degree of residual gastric secretions, the peristaltic activity detected by endoscopists, and the comfort experienced by the patients in each study group. CONCLUSIONS: The intramuscular injection of cimetropium bromide (5 mg) as a premedication for EGD was not significantly superior to placebo, at least with respect to subjective parameters, in spite of its broad use.