This prospective study compared admitting prescription medication orders with a comprehensive medication history obtained through interview. Investigators aimed to evaluate the differences between the two sets of medication lists to demonstrate the number of discrepancies. Results demonstrated that more than half of the study participants had at least one unintended discrepancy. The most common errors included ones of omission, and the majority of the errors led to no significant harm but some discomfort or clinical deterioration. The authors discuss the potential for intervention to reduce these types of medication errors and the role of pharmacists in assisting with accurate medication histories.