International Opium Convention

The International Opium Convention was the first drug control treaty (or agreement). It was signed at The Hague in The Netherlands on January 23, 1912. The United States organised a conference between 13 countries called the International Opium Commission in 1909 in Shanghai, China because people complained more and more about opium trade. The treaty was signed by Germany, the United States, China, France, the United Kingdom, Italy, Japan, The Netherlands, Persia, Portugal, Russia, and Siam. The Convention said that "The contracting Powers shall use their best endeavours to control, or to cause to be controlled, all persons manufacturing, importing, selling, distributing, and exporting morphine, cocaine, and their respective salts, as well as the buildings in which these persons carry such an industry or trade."
The Convention was implemented in 1915 by the United States, Netherlands, China, Honduras, and Norway. It went into force around the world in 1919 when it became part of the Treaty of Versailles.
A modified International Opium Convention was signed on February 19, 1925, which started on September 25, 1928. It introduced control system to be looked after by a Permanent Central Opium Board, part of the League of Nations. Egypt, with support from 
China and United States, recommended that a ban on hashish be added to the Convention.
India and other countries did not agree, saying social and religious customs and that wild-growing cannabis plants being available in many places, that would make it difficult to enforce, so this never made it into the final treaty. A compromise was made that banned the export of "Indian hemp" to countries that have banned its use. Importing countries were made to issue certificates approving the import and stating that the shipment was required "exclusively for medical or scientific purposes." It also required Parties to "exercise an effective control of such a nature as to prevent the illicit international traffic in Indian hemp and especially in the resin." These restrictions still made it easy for countries to allow production, internal trade, and use of cannabis for recreational purposes.
The Convention was superseded by the 1961 Single Convention on Narcotic Drugs.