1922: Pioneering feminist Emily Murphy publishes an inflammatory book, The Black Candle. She claims marijuana turns its users into homicidal maniacs.
1923: Cannabis is added to the Schedule of the Opium and Narcotic Control Act.
1969: Canadian government establishes a Commission of Inquiry Into the Non-Medical Use of Drugs, known as the Le Dain commission after its chairman, Gerald Le Dain.
1972: The commission recommends decriminalizing simple cannabis possession and cultivation for personal purposes.
1976: The Netherlands effectively decriminalizes marijuana.
1977: Then-prime minister Pierre Trudeau tells a group of students: "If you have a joint and you're smoking it for your private pleasure, you shouldn't be hassled."
1978: New Mexico passes the first state law recognizing the medical value of marijuana.
1996: California becomes the first state to legalize medical marijuana.
1999: Two Canadian patients get the federal OK to smoke pot.
2000: Court rules Canadians have a constitutional right to use cannabis as a medicine.
2001: Canadian Medical Marihuana Access Regulations grant legal access to cannabis for individuals with HIV/AIDS and other illnesses. Authorized patients can grow their own pot or obtain it from authorized producers or Health Canada.
2012: Ballot measures in Colorado and Washington legalize recreational use of small amounts of marijuana.
2013: New regulations change the Canadian medical marijuana access rules, shifting to licensed commercial growers for supply and away from homegrown. Some 37,800 people authorized to possess marijuana under the federal program, up from fewer than 100 in 2001.
2014: Patients and producers authorized under the old regulations required to destroy stocks of pot and cannabis seeds, although a Federal Court has granted a temporary injunction allowing continued use of home-grown medical marijuana until legal arguments can be heard.