This study of geriatric patients discharged from a teaching hospital emergency department (ED) found that nearly 20% did not understand either their diagnosis or how to care for themselves at home, and the majority did not know the expected course of their illness or when to return to the ED. The study corroborates prior research showing that many ED patients do not comprehend their discharge instructions, and that a large proportion of hospitalized patients are unaware of their diagnosis. Many factors may play a role in this discrepancy, including low health literacy and suboptimal patient–provider communication. An AHRQ WebM&M perspective discusses the broader issue of patient safety in the emergency department.