Strain Library

Cannabis timeline · 1937 to 1969

Prohibition and discovery

4 milestones from 1937 to 1964: the Marihuana Tax Act; cannabis dropped from the US Pharmacopoeia; the UN Single Convention on Narcotic Drugs; and more.

1937

The Marihuana Tax Act

Law & policy

Congress taxed marihuana dealers and transfers, creating the first federal restrictions on cannabis use and sale. The act was approved on August 2, 1937.

Sources (2)
  1. 50 Stat. 551 (govinfo)
  2. Bridgeman and Abazia (2017), P&T (PMC)

1942

Cannabis dropped from the US Pharmacopoeia

Medicine

Cannabis was removed from the United States Pharmacopoeia, ending its standing as a recognized prescription medicine a few years after the 1937 federal tax law.

Only secondary sources give the year.

Sources (2)
  1. Bridgeman and Abazia (2017), P&T (PMC)
  2. National Academies Press online chapter

1961

The UN Single Convention on Narcotic Drugs

Law & policy

Adopted in New York on March 30, 1961 and in force from December 1964, this treaty placed the cannabis plant under international control.

Sources (2)
  1. UN Treaty Collection status page (VI-15)
  2. UN Treaty Collection: Convention text (excerpt)

1964

THC is isolated and its structure described

Science

Chemists in Israel isolated delta-9-THC from hashish and described its structure in a paper published in the Journal of the American Chemical Society in 1964.

Sources (2)
  1. Mechoulam and Hanus (2000), Chemistry and Physics of Lipids
  2. World of Cannabis Museum

Written from the listed sources. Not legal or medical advice. Reviewed October 19, 2026.