Essential medicines are those that satisfy the priority health care needs of the population. They are intended to be available within the context of function health systems at all times, in adequate amounts, in the appropriate dosage forms, of assured quality and at prices that individuals and the community can afford. The WHO Model Lists of Essential Medicines serve as a guide for the development and updating of national and institutional essential medicine lists to support the procurement and supply of medicines in the public sector, medicines reimbursement schemes, medicine donations, and local medicine production.

The Expert Committee on the Selection and Use of Essential Medicines is responsible for providing recommendations to WHO regarding medicines on the WHO Model List of Essential Medicines (EML) and Model List of Essential Medicines for Children (EMLc). 

The Committee meets every two years to review applications for the addition, amendment or deletion of medicines on the Model Lists, taking into consideration the disease prevalence and public health relevance, scientific evidence of efficacy and safety, and comparative cost and cost-effectiveness. 

Members of the Expert Committee are selected from WHO Expert Advisory Panels based on their professional expertise and experience, while also ensuring equitable geographical and gender balance in order to provide representation and practical experience from all regions of the world and across settings of all income levels.