Essential medicines are intended to be available within the context of functioning health systems at all times in adequate amounts, in the appropriate dosage forms, with assured quality, and at a price the individual and the community can afford.

The Model List is a guide for the development of national and institutional essential medicine lists. It was not designed as a global standard. However, for the past 30 years the Model List has led to a global acceptance of the concept of essential medicines as a powerful means to promote health equity. Most countries have national lists and some have provincial or state lists as well. National lists of essential medicines usually relate closely to national guidelines for clinical health care practice which are used for the training and supervision of health workers.