This survey revealed that many adults do not understand instructions for common liquid prescription medications, potentially increasing the risk of serious medication errors. Prior research in this field has demonstrated that low health literacy is an important predictor of misunderstanding prescription instructions. Concerningly, in this study nearly 1 in 5 patients who had adequate health literacy could not correctly interpret the instructions, and patients with marginal or low health literacy were at even greater risk. A previous WebM&M commentary discusses safety problems caused by low health literacy.