The WHO Model List of Essential Medicines is revised every two years and guides the national lists of over 150 countries

Background

Essential medicines are those that effectively and safely treat the priority health-care needs of populations, and should be available, affordable and of assured quality at all times.
WHO selects them on the basis of public health relevance, evidence of benefits and harms, and with consideration of costs, affordability and other relevant factors.
Every 2 years since 1977, WHO has published the WHO Model List of Essential Medicines, also known as the Essential Medicines List or EML; the first list included about 200 medicines.
A separate Model List of Essential Medicines for Children (EMLc) was first published in 2007, in recognition of the unique needs of children.
Over 150 countries have national essential medicines lists based on the WHO Model List, and those lists are used for procurement, reimbursement, insurance schemes, medicine donations and local production.
Requests to add, remove or extend the listing of a medicine come through an open application process and are reviewed by the WHO Expert Committee on Selection and Use of Essential Medicines, whose members are appointed by the WHO Director-General.
The Model List carries the AWaRe (Access, Watch, Reserve) classification of antibiotics, which guides the empiric use of essential antibiotics for more than 30 clinical infections in community and hospital settings.