Poor health literacy has been identified as an important threat to patient safety, particularly through potentially contributing to adverse drug events. In this study, researchers surveyed patients in three urban primary care clinics serving predominantly indigent populations, and found that low health literacy was independently associated with misunderstanding of prescription drug label instructions. Although the study did not directly evaluate if misunderstanding led to medication errors, the study adds to a growing body of research documenting that patients with low and marginal health literacy have difficulty comprehending prescribing information. In the accompanying editorial, Dr. Dean Schillinger calls for development of standardized systems for transmitting medication instructions to patients in a clear and understandable fashion.