This study discovered that a preprinted and structured order form was half as likely to be associated with a medication error compared with use of traditional blank order forms. Using two pediatric emergency physicians who were blinded to the order form type, investigators report differential rates and severity of medication errors from physician review of patient charts. The study is the first randomized controlled trial to demonstrate that a low-cost intervention can significantly reduce medication errors in pediatric emergency room patients. Such order sets may provide a useful tool while many hospitals await full implementation of computerized physician order entry systems.