[영문]Purpose. The implementation of vendor-based integrated clinical information technology was studied, and its effect on medication errors throughout the medication-use process in a health care system was evaluated. Methods. The integrated systems selected for implementation included computerized physician order entry, pharmacy and laboratory information systems, clinical decision-support systems (CDSSs), electronic drug dispensing systems (EDDSs), and a bar-code point-of-care medication administration system. The primary endpoint was the reduction in related medication errors. Secondary endpoints included the reductions in medication order turnaround time and EDDS override transactions. Results. Integrated clinical information system technology was implemented in a multihospital health care system with a phased-in approach. A positive effect of this integration on medication errors throughout the medication-use process was demonstrated. Most prescribing errors decreased significantly in the selected categories monitored, specifically drug allergy detection, excessive dosing, and incomplete or unclear orders. Pharmacists were also twice as likely to identify dosages requiring adjustment for renal insufficiency when the integrated technology was in place and more than six times as likely for drug levels outside of the therapeutic range. A positive effect on medication administration safety was also demonstrated: 73 administration-related errors were intercepted through electronic bar-code scanning for every 100,000 doses charted. Conclusion. Integration of clinical information system technology decreased selected types of medication errors throughout the medication-use process in a health care system and improved therapeutic drug monitoring in patients with renal insufficiency and in patients receiving drugs with narrow therapeutic ranges through the use of CDSS alerts