The essential medicines list for a global patient population.

Thirty years after its inception, the role, audience, and contents of the global Essential Medicines List (EML) are reviewed. Challenges for decision makers in applying the principles of medicine selection based on efficacy, safety, burden of disease, and cost effectiveness are discussed and illustrated with recent decisions of the Expert Committee. Areas of controversy for decision makers are highlighted, and the advocacy role of the EML for both drug procurement and development of quality-assured products is described.