The Single Convention on Narcotic Drugs, 1961, is the main international treaty controlling cannabis. It consolidated earlier drug treaties and requires parties to limit the production, trade and use of listed substances to medical and scientific purposes, with licensing, estimates and reporting. It was amended by a 1972 Protocol.
In practice
Cannabis, cannabis resin and extracts are listed in its schedules. In December 2020 the UN Commission on Narcotic Drugs voted to remove cannabis from Schedule IV, the category for drugs considered particularly dangerous with little medical value, while keeping it in Schedule I. The convention explicitly excludes cannabis grown exclusively for industrial (fibre and seed) or horticultural purposes.
Countries that legalise adult-use cannabis are, in strict treaty terms, in tension with the convention, and have argued their positions in different ways. The treaty shapes national law but does not itself set penalties.
Rules differ by country, state, province and city, and change often. This is a general definition, not legal advice: check local rules.
Don't confuse with
- 1971 Convention on Psychotropic Substances: lists THC (dronabinol) as a substance.
- National scheduling: each country's own drug classification.
