A patient was admitted to the hospital and received 3 times his normal dose of phenytoin, resulting in phenytoin toxicity and a long hospital stay. Analysis of the error revealed problems with hospital organization, supervision issues, and having an environment that facilitates errors. Errors don't occur simply because one clinician makes a mistake—rather, they occur because the hospital system fails to prevent them. We interview Robert S. Hendler, MD, from Parkland Health and Hospital System in Dallas, Texas, and Nadine Shehab, PharmD, MPH from the Centers for Disease Control and Prevention.