Patients presenting to an emergency department (ED) with an adverse drug event (ADE) are a source of continued concern, particularly as many ADEs are thought to be preventable. This prospective study compared patients presenting to the ED because of ADEs to those presenting for other reasons. Investigators found that patients presenting with an ADE had a higher risk of spending additional hospital days per month, a higher rate of outpatient encounters, and nearly double the costs of care incurred during a 6-month follow-up period. A past AHRQ WebM&M perspective discusses the broader aspects of providing safe care in the emergency department setting.