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Major Studies of Drugs and Drug Policy
Canadian Senate Special Committee on Illegal Drugs
Volume 3 - Public Policy Options

Chapter 19 - The International Legal Environment

The 1931 Geneva Narcotics Manufacturing and Distribution Limitation Convention / 1931 Bangkok Opium Smoking Agreement

The import control system put in place following the 1925 Geneva Convention was only partially effective, as drugs were simply transhipped through non-signatory countries. In 1931, the League of Nations convened a further conference in Geneva to place limits on the manufacture of cocaine, heroin and morphine, and to control their distribution. The result of the conference was the Convention for Limiting the Manufacture and Regulating the Distribution of Narcotic Drugs[1][30] (1931 Limitation Convention).

In 1931, Canada abandoned its policy of simply reacting to international drug control efforts and began playing an active role in supporting U.S. efforts to expand control at the source. Colonel Charles Henry Ludovic Sharman, Chief of the Narcotics Division in the Department of Pensions and National Health, was the principal architect of Canada’s domestic and international drug policy until the 1960s. Canada, through Sharman, was heavily involved in the negotiations leading up to the 1931 Limitation Convention.[2][31]

A new player also emerged from within the U.S. delegation: Harry J. Anslinger, first Commissioner of the newly created Federal Bureau of Narcotics, a position he would hold for 33 years. A firm believer in prohibition and the control of drug supplies at the source, Anslinger is widely recognized as a prime mover in the development of U.S. drug policy and, by extension, international drug control into the early 1970s.[3][32]

The centrepiece of the 1931 Limitation Convention was the manufacturing limitation system set out in Chapters II and III. Parties were required to provide the PCOB with estimates of their national drug requirements for medical and scientific purposes, and on the basis of those estimates, the PCOB would calculate manufacturing limits for each signatory. A Drug Supervisory Body (DSB) was created to administer the system. The Convention’s effectiveness was seriously undermined by Article 26, which absolved states of any responsibilities under the Convention for their colonies. Article 15 required states to set up a “special administration” for national drug control, modelled to some extent on the U.S. domestic control apparatus.[4][33]

The Convention came into force quickly because various countries and the League of Nations thought it might provide a useful model for arms control negotiations. The League even prepared a report explaining how the principles set out in the 1925 Geneva Convention and the Limitation Convention could be applied to disarmament issues.[5][34]  

In late 1931, another conference was held in Bangkok to address opium smoking in the Far East. The treaty[6][35] it produced was weak, primarily because the U.S. attended only as an observer and the European colonial powers were unwilling to implement effective controls on opium use while there was significant opium overproduction and smuggling. The fact that the U.S. strategy of absolute prohibition had made little impact on opium trafficking and use in the Philippines did not strengthen the U.S.’s hand in pushing for the elimination of poppy cultivation. The key result of the Bangkok conference was that it convinced the U.S. that a firmer approach was needed to combat raw material production and illicit drug trafficking.[7][36]  


[1][30]  Done 13 July 1931; in force 9 July 1933.

[2][31]  Giffen et al. (2000), page 483.

[3][32]  See, for example, McAllister (2000), page 89-90; Bewley-Taylor (1999), page 102-164; Bruun et al. (1975), page 137-141; Inglis (1975), page 181-190. See also Harry J. Anslinger and Will Oursler, “The War against the Murderers,” in William O. Walker III, ed., Drugs in the Western Hemisphere: An Odyssey of Cultures in Conflict, Wilmington, Delaware: Scholarly Resources Inc., 1996.

[4][33]  Anslinger would use this provision continually in the future as a way of protecting his position and the Federal Bureau of Narcotics from being altered through reorganization. (McAllister (2000), page 98, 108-109)

[5][34]  Ibid., page 110-111.

[6][35]  Agreement for the Control of Opium Smoking in the Far East, done 27 November 1931, in force 22 April 1937.

[7][36]  Taylor (1969), page 275-279; McAllister (2000), page 106.

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