WHO World Health Organisation

The 1925 Brussels Pharmacopoeia Agreement and Geneva Opium Convention were foundational in shaping international pharmaceutical regulation. The former sought to standardise potent medicines, while the latter established controls over psychoactive substances. Despite differing objectives, both treaties influenced global pharmaceutical governance, contributing to modern regulatory frameworks and standards such as those of WHO or the European Pharmacopoeia. A century later, the year 2025 is witness to turbulent shifts in geopolitics and global health governance, but also revived contemporary debates on drug policy and traditional medicines. This letter revisits the seldom-documented history and impact of international pharmacy law, highlighting the relevance of these two pioneering treaties to evolving pharmaceutical governance and international health law.

Background: In 2016-2019, the WHO Expert Committee on Drug Dependence scientifically reviewed cannabis products. In that context, multiple references to a previous and similar assessment dating back to 1935 were made; but the content, outcome, and stakeholders involved in the 1935 review were unclear.

Method: Transnational historiography of the international conversation on cannabis control in and around 1935, based on previously-unavailable primary material from international organisations, archives, and literature searches.

Results: Two evaluations were undertaken in 1935 and 1938 by the “Comité des Experts Pharmacologistes” convened under the “Office International d’Hygiène Publique” (OIHP), predecessor of the WHO. Five specific medicines marketed by Parke-Davis were briefly reviewed, based on which the Experts recommended placing under international control all cannabis medicines –prior to that, only pure extracts were under control. The measure was confusing; few State Parties to the 1925 Convention implemented it; the second World War precipitated its oblivion. The international community resumed work on cannabis under the WHO in 1952; that same year, the OIHP was definitely closing its doors. No trace of the 1935 events appeared in any post-war proceeding.

Conclusion: Political biasses and numerous methodological and ethical issues surround the 1935 episode: it cannot legitimately be called a “scientific assessment.” The role of stakeholders like Egypt and the OIHP in norm entrepreneurship and advocacy for multilateral controls over cannabis have been largely forgotten; that of the USA somewhat exaggerated. There might be other forgotten pieces of History: predecessor of WHO, the under-documented OIHP had mandates on other important fields, be it drug or epidemics control. Much knowledge on the History of humankind lays in unexplored archival records; errors made and lessons learnt from the past could inform our management of the conflict between public health and politics today. 

Background – ‘‘Cannabis’’ and ‘‘cannabis resin’’ are derived from the Cannabis plant, used as herbal medications, in traditional medicine and as active pharmaceutical ingredients. Since 1961, they have been listed in Schedule IV, the most restrictive category of the single convention on narcotic drugs. The process to scientifically review and reschedule them was launched by the World Health Organisation (WHO) on 2 December 2016; it survived a number of hindrances until finally being submitted to a delayed and sui generis vote by the UN Commission on Narcotic Drugs on 2 December 2020, withdrawing ‘‘cannabis’’ and ‘‘cannabis resin’’ from Schedule IV.

Design/methodology/approach – To evaluate WHO’s scheduling recommendations, the process leading to the Commission vote and subsequent implications at global, national and patient/clinician levels. Narrative account of the four-year proceedings; review of the practical implications of both rejected and accepted recommendations.

Findings – The process was historically unprecedented, of political relevance to both medical Cannabis and evidence-based scheduling generally. Procedural barriers hampered the appropriate involvement of civil society stakeholders. The landscape resulting from accepted and rejected recommendations allow countries to continue creating decentralised, non-uniform systems for access to and availability of ‘‘cannabis’’ and ‘‘cannabis resin’’ for medical purposes.

Originality/value – Perspective of accredited observers; highlight of institutional issues and the lay of the land; contrast of stakeholders’ interpretations and engagement.