April 19, 1943: Albert Hoffman takes the first dose of LSD, in Basel, Switzerland.

April 23, 1998: The Ottawa Citizen reports that Canadians who tell US border officials the truth about their past use of marijuana will be denied entry to America indefinitely.

April 18, 2001: Kenneth Hayes and Michael Foley are acquitted by a Sonoma County, California jury on charges of cultivating and possessing marijuana. The two were arrested for growing 899 marijuana plants for the 1,200 members of a San Francisco medical marijuana club called CHAMP (Cannabis Helping Alleviate Medical Problems).

April 20, 2001: American Christian missionary Veronica Bowers and her seven month-old daughter, Charity, are killed when their small plane is shot out of the sky by a Peruvian military jet as part of a CIA-backed program that patrols the Amazon Basin for drug couriers. The Senate Intelligence Committee investigates and concludes the missionary pilot did nothing wrong and should not have come under fire.

April 17, 2002: While under the influence of amphetamines issued to them by the US government in order to stay awake during the mission, two US pilots mistakenly drop a bomb that kills four Canadian soldiers in Afghanistan. The Air Force-issued "go pills" may have impaired the pilots' judgment, says David Beck, lawyer for Maj. William Umbach, adding that the pilots were given antidepressants upon returning from their mission. "The Air Force has a problem. They have administered 'go pills' to soldiers that the manufacturers have stated affect performance and judgment," Beck said.

April 20, 2002: Robin Prosser of Missoula, Montana begins a hunger strike demanding access to government grown marijuana to help her treat symptoms of Lupus. Prosser says that marijuana helps combat the illness and relieves her pain and stress.

April 21, 2004: US Circuit Court Judge Jeremy Fogel bars the US Dept. of Justice from interfering with Mike and Valerie Corral, heads of a medical marijuana hospice near Santa Cruz, California, with their 250 patients, or with their marijuana garden. Judge Fogel cites Raich v. Ashcroft, a 2004 Ninth Circuit decision which found the federal government has no jurisdiction over patients who grow their own plants.

April 22, 2004: The Pacific edition of the magazine Stars and Stripes reports that twenty sailors assigned to Commander, Naval Forces Marianas (Guam) were arrested on drug-related charges since late 2003 alone.