The WHO Model List of Essential Medicines: How It Is Chosen

The World Health Organization's Model List of Essential Medicines (EML) is one of the most influential public health documents in the world. Since its first edition in 1977, it has served as a guide for countries developing their own national essential medicines lists — catalogues of the medicines a health system needs to have available, at all times, in adequate amounts, and at a price the system can afford. The list is not a regulatory document; it does not approve or ban medicines. Rather, it is a recommendation that governments, procurement agencies, and health institutions use as a starting point for deciding which medicines to prioritise.

The underlying idea is straightforward: no health system can stock every medicine, and many countries face significant resource constraints. Identifying a core set of essential medicines helps focus limited budgets on the treatments that provide the greatest public health benefit. The concept was introduced by WHO in 1975 and formalised with the first EML two years later. Today, the list is widely used as a reference by national governments, UN agencies, and global health donors.

How medicines are selected

Responsibility for the EML rests with the WHO Expert Committee on Selection and Use of Essential Medicines, a panel of independent specialists in clinical medicine, pharmacology, public health, and related fields. Committee members are appointed in their personal capacity, not as representatives of any government or organisation, and they serve staggered terms to ensure continuity of expertise.

Selection is evidence-based. Any institution, organisation, or individual can submit an application to add a medicine, change its listing, or remove it. Applications must include detailed evidence: clinical trial data, systematic reviews, and information on cost, comparative effectiveness, and public health relevance. The committee evaluates this evidence against criteria that include the medicine's benefit–harm profile, its value relative to alternatives, and whether it addresses priority health needs — particularly those of low- and middle-income countries.

Importantly, the EML does not attempt to compare every drug in a therapeutic class. It identifies a medicine as essential if it satisfies the health needs of the majority of the population. In some cases, more than one medicine from the same class appears, usually because they serve different patient populations or have different safety profiles. A square box symbol (☐) next to a listing indicates that the medicine is an example of a therapeutic class and that other medicines in the same class could be considered alternatives depending on local circumstances.

The biennial review cycle

The EML is updated every two years. This regular revision keeps the list current with evolving medical evidence, changing disease burdens, and new safety findings. The process begins well before the expert committee meets. WHO issues a call for applications, which are submitted and published online for public review — a step that adds transparency and allows the wider community to comment.

The expert committee then meets to deliberate on the applications. It reviews the evidence, discusses the merits of each proposal, and makes decisions. A meeting report is published explaining the rationale for each decision — which applications were accepted, which were rejected, and why. This report is itself a valuable resource for national medicines committees, as it documents the evidence base behind each listing choice. Between formal updates, the committee can also issue guidance on specific questions, for example recommending the addition of a medicine in response to a public health emergency.

How countries adapt the list

The WHO EML is explicitly a model — a template, not a mandate. WHO guidance encourages countries to use it as a starting point and adapt it to local epidemiology, available infrastructure, health workforce capacity, and budgetary realities. A medicine listed on the WHO EML may be omitted from a national list if the disease it treats is rare in that country, or if the medicine requires cold-chain storage that local facilities cannot reliably provide.

Many countries maintain their own essential medicines lists, updated on their own schedules. In South Africa, the National Essential Medicines List is maintained under the National Department of Health, with separate committees for adult and paediatric medicines. The South African EML guides procurement for public-sector facilities and is linked to standard treatment guidelines. It is separate from SAHPRA's registration process: a medicine must be registered by SAHPRA before it can be marketed, while inclusion on the EML determines whether it is prioritised for public-sector supply. Users of HealthSA can check whether a medicine is SAHPRA-registered, while the SA EML itself is available through the National Department of Health.

The EMLc for children

Recognising that children's medication needs differ substantially from those of adults — in dosing, in available formulations, and in the diseases that affect them — WHO introduced a separate Model List of Essential Medicines for Children (EMLc) in 2007. The EMLc is updated alongside the adult list and follows the same evidence-based process.

The EMLc addresses a longstanding gap. Many medicines were historically developed and tested only in adults, leaving clinicians to estimate children's doses or manipulate adult formulations. The EMLc highlights where age-appropriate formulations — such as dispersible tablets or oral liquids — are needed, and its existence has encouraged greater attention to paediatric drug development. Together, the adult and paediatric lists provide a comprehensive picture of the medicines that WHO considers most vital for addressing the world's health needs.