The essential medicines concept is a global concept that can be applied in any country, in the private and public sectors and at different levels of the health care system. It promotes equity and helps to set priorities for the health care system. The core of the concept is that the use of a limited number of carefully selected medicines based on agreed clinical guidelines leads to a better supply of medicines, to more rational prescribing and to lower costs. There is substantial evidence that the use of national lists of essential medicines has contributed to an improvement in the quality of care and to a considerable saving in medicine costs.