In this study, a survey was conducted to determine the rate of drug-dispensing errors with the use of medicine bags printed with photographs of prescribed medicines (hereafter "medicine bag") for a 6-week period from June 20 to July 31, 2005. During this period, 393928 prescriptions were filled in 127 medical facilities that use the medicine bag. The efficacy of the medicine bag in the prevention of drug-dispensing errors was investigated. A total of 6550 (1.66%) drug-dispensing errors were identified: 70.6% were identified at the inspecting stage; 27.4% at the providing medicine and information stage; and 2% after the medication was dispensed. The drug-dispensing errors identified in the inspecting and providing stages included a) using the wrong contents, b) dispensing the wrong drugs, c) missing drugs, d) calculation errors, e) weighing/measuring errors, and f) others. No significant difference was observed in the error rates; thus it was assumed that the type of error was not dependent on the stage at which dispensing errors was discovered. However, it was found that approximately 25% of errors at the providing stage were discovered as a result of the medicine bag. Errors of types a), b), and c) were often discovered because the photograph was printed on the medicine bag. Therefore it was assumed that the photographs contributed to the discovery of drug-dispensing errors.