Drug use evaluation (DUE) has been employed in the US hospital setting for more than 30 years as a means of influencing the prescribing behaviour of physicians. Recently, federal legislation was introduced requiring DUE for ambulatory patients receiving medication through federally funded programmes. The process of DUE is designed to ensure the rational use of medications in the treatment and prevention of disease, according to Dr Gary Smith from the University of Arizona College of Pharmacy, Tucson, US.†