This AHRQ–funded study discovered that the use of alerts within an electronic medical record system can reduce the number of unsafe medications prescribed in elderly outpatients. Investigators evaluated the impact of a clinical decision support system (CDSS) at the point of computerized provider order entry (CPOE), targeting two classes of contraindicated medications (long-acting benzodiazepines and tertiary amine tricyclic antidepressants). The authors discuss the rapid, significant, and persistent reductions in medication prescribing of these high-risk medications, suggesting the effectiveness of an alert system to curtail inappropriate prescribing. This study is a first to evaluate a computerized alert system in a large population-based primary care setting, although a past systematic review evaluated the effects of CDSS on practitioner performance and patient outcomes.