Medical marijuana

Introduction
Pros
- Pro 1: Marijuana is beneficial as a medicine with fewer risks than opioids and other prescribed drugs.
- Pro 2: Marijuana is safer than some legal drugs and preferred by patients.
- Pro 3: Americans have agreed for decades that medical marijuana should be legal.
Cons
- Con 1: Studies of the medical use of marijuana are not reassuring—they’re alarming.
- Con 2: Marijuana has dangerous side effects.
- Con 3: Medical legalization of marijuana makes a dangerous drug more available to everyone, including children.
State-by-state medical marijuana laws
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- D.C.
- Florida
- Hawaii
- Illinois
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Dakota
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
Marijuana studies
- February 20, 2026 - Teen cannabis use tied to increased risk of psychiatric disorders
- November 26, 2025 - Review of 15 years of cannabis research reveals little evidence of medical benefit and an increase in medical problems
- November 18, 2025 - Cannabis use may lead to decreased alcohol use
- October 28, 2025 - Smoking cannabis in youth associated with more medical problems later in life
- October 2025 - American College of Obstetricians & Gynecologists advise against cannabis use during pregnancy
- September 30, 2025 - Cannabis extract better than opioids for back pain
- September 29, 2025 - Cannabis extract shown to help chronic low back pain
- June 17, 2025 - Cannabis use associated with major adverse cardiovascular events
- June 2, 2025 - Marijuana use among older adults has increased
- June 1, 2025 - Cannabis hospitalizations associated with increased risk of new dementia diagnosis
- May 28, 2025 - Chronic cannabis use associated with endothelial dysfunction
- May 14, 2025 - Cannabis use and cannabis use disorder common among older veterans
- April 10, 2025 - Smoking remains most popular method of cannabis consumption
- February 6, 2025 - Cannabis use disorder hospitalizations linked to premature death
- February 4, 2025 - Cannabis use disorder association with schizophrenia has increased
- January 28, 2025 - Heavy marijuana use associated With lower brain activation during working memory tasks
- January 2025 - Cannabis use linked to arrhythmias
- June 18, 2024 - Cannabis-related healthcare encounters increased
- March 9, 2024 - Cannabis flowers’ THC content regularly mislabeled in dispensaries
- February 28, 2024 - Cannabis use associated with adverse cardiovascular outcomes
- August 1, 2023 - Daily cannabis smoking perceived as safer than daily tobacco smoking
- May 4, 2023 - Young men with cannabis use disorder have increased risk of developing schizophrenia
- April 2023 - Cannabis-related ER visits increased
- May 26, 2021 - Perceived risk of regular cannabis use declines among older adults
U.S. surgeons general: Views on medical marijuana
- Vivek Murthy: Not Clearly Pro or Con
- Jerome Adams: Not Clearly Pro or Con
- Vivek Murthy: Not Clearly Pro or Con
- Regina M. Benjamin: Not Clearly Pro or Con
- Richard H. Carmona: Not Clearly Pro or Con
- David Satcher: Now Pro / Formerly Con
- M. Joycelyn Elders: Pro
- Antonia C. Novello: No Position Found
- C. Everett Koop: Con
- Julius B. Richmond: Not Clearly Pro or Con
- Jesse L. Steinfeld: Pro
Votes and polls on medical marijuana
- 2022
  - Dallas Morning News & University of Texas at Tyler: September 6-13, 2022
  - Nebraska Annual Social Indicators Survey, published in the Journal of Drug Issues: May 17, 2022
  - BenchMark Research: April 8-11, 2022
  - WGHP, The Hill, & Emerson College: April 2-4, 2022
- 2021
  - Pew Research Center: April 5-11, 2021
  - Starboard Communications: February 16-19, 2021
  - Starboard Communications: January 29-31, 2021
- 2020
  - Wyoming Survey and Analysis Center (WYSAC) at the University of Wyoming: December 7, 2020
  - Nexstar Media Group & Emerson College: September 2020
  - Foundation for a Healthy Kentucky (conducted by the Institute for Policy Research at the University of Cincinnati) Poll: February 2020
- 2019
  - Pew Research Center: September 3-15, 2019
  - Axios and SurveyMonkey: June 6-9, 2019
  - Quinnipiac University: March 1-4, 2019
  - Benchmark Research: January 2019
- 2018
  - Mason-Dixon Polling & Strategy: December 6-10, 2018
  - Missouri Scout: August 8-9, 2018
  - Quinnipiac University: April 26, 2018
  - Dan Jones & Associates: February 9-16, 2018
  - Selzer and Co. of Des Moines: January 28-31, 2018
- 2017
  - Mason-Dixon Polling & Strategy: December 6-19, 2017
  - Elon University: April 18-21, 2017
  - Fairbank, Maslin, Maullin, Metz & Associates: February 17-19, 2017
- 2016
  - News 13 (Orlando) & Bay News 9 (Tampa Bay): March 9, 2016
  - UtahPolicy.com & Dan Jones and Associates: February 10-15, 2016
- 2015
  - UtahPolicy.com & Dan Jones and Associates: November 5-15, 2015
  - Harris Poll: May 7, 2015
  - Talk Business & Politics, Hendrix College, & Impact Management Group: August 20-23, 2015
  - Quinnipiac University: March 17-28, 2015
  - Quinnipiac University: March 17-28, 2015
  - Quinnipiac University: March 17-28, 2015
  - UtahPolicy.com & Dan Jones and Associates: March 3-5, 2015
  - Libertas Institute and Drug Policy Project of Utah: February 26-28, 2015
  - Des Moines Register Iowa Poll: February 15-18, 2015
- 2014
  - University of Wyoming Department of Political Science, Wyoming Public Radio, & Wyoming Survey and Analysis Center: December 3, 2014
  - Florida General Election: November 4, 2014
  - Bob Graham Center for Public Service, University of Florida Bureau of Economic and Business Research, Tampa Bay Times, & Bay News 9: September 4, 2014
  - Quinnipiac University: May 5, 2014
- 2013
  - Quinnipiac University: November 21, 2013
  - New England Journal of Medicine: May 30, 2013
  - WMUR Granite State Poll & University of New Hampshire Survey Center: February 12, 2013
  - USC Dornsife College of Letters, Arts, and Sciences & Los Angeles Times: February 12, 2013
- 2012
  - Reason/Rupe: September 13-17, 2012
  - Quinnipiac University: March 21, 2012
- 2011
  - CBS News: October 28-31, 2011
  - Quinnipiac University: March 10, 2011
- 2010
  - Hawkeye Poll Cooperative at the University of Iowa: November 3-11, 2010
  - Arizona Election: November 2, 2010
  - South Dakota Election: November 2, 2010
  - Gallup Organization: October 7-10, 2010
  - KCCI News Channel 8: June 3, 2010
  - Associated Press & CNBC: April 7-12, 2010
  - Des Moines Register: February 16, 2010
  - ABC News & Washington Post: January 15, 2010
- 2009
- 2008
  - Michigan Election: November 4, 2008
- 2007
- 2006
  - South Dakota Election: November 7, 2006
- 2005
  - Chamberlain Research Consultants for Marijuana Policy Project (MPP): July 2005
  - Mason-Dixon Polling & Marijuana Policy Project: June 2005
- 2004
  - Montana Election: November 2, 2004
  - AARP National Poll by ICR Poll: November 2004
  - Scripps Research Center in Abilene for Texans For Medical Marijuana: November 2004
  - Field Poll: January 2004
- 2003
  - Zogby International: August 2003
- 2002
  - Harris Interactive for Time Magazine: October 2002
  - Social Research Laboratory: September 2002
  - Lucas Organization and Arlington Research Group: March 2002
  - Lucas Organization and Arlington Research Group: February 2002
  - Lucas Organization and Arlington Research Group: February 2002
  - Lucas Organization and Arlington Research Group: February 2002
  - Lucas Organization and Arlington Research Group: February 2002
  - Lucas Organization and Arlington Research Group: February 2002
  - Lucas Organization and Arlington Research Group: February 2002
  - Lucas Organization and Arlington Research Group: February 2002
  - Lucas Organization and Arlington Research Group: February 2002
  - Lucas Organization and Arlington Research Group: February 2002
  - Lucas Organization and Arlington Research Group: February 2002
  - Lucas Organization and Arlington Research Group: February 2002
  - Chamberlain Research: February 2002
  - Center for Substance Abuse Research, University of Maryland: January 2002
  - Gonzales/Arscott Research: January 2002
- 2001
  - Zogby International for NORML: December 2001
  - University of Arkansas Survey Research Center: October 2001
  - Virginia Tech Center for Survey Research: June 2001
  - Gonzales/Arscott Research: May 2001
  - Researchers at Rhode Island Hospital for presentation to American Society of Addiction Medicine: April 2001
  - Pew Research Center: March 2001
  - Research Polling, Inc.: March 2001
  - Lazarus Strategic Services: January 2001
  - Creative Broadcast Systems, Inc.: January 2001
- 2000
  - Nevada Election: November 2000
  - Colorado Election: November 2000
  - Denver Post, 9 News, & KOA Radio: October 2000
  - Denver Rocky Mountain News & News 4: September 2000
  - Mason-Dixon Research Poll: September 2000
  - QMark Research & Polling on behalf of The Drug Policy Forum of Hawaii: February 2000
  - Center for Substance Abuse Research at University of Maryland: January 2000
Historical timeline
- 2900 BC-1599 AD
  - 2900 BC - Chinese Emperor Fu Hsi references marijuana as a popular medicine
  - 2700 BC - Chinese Emperor Shen Nung said to discover healing properties of marijuana
  - 1450 BC - Book of Exodus references holy anointing oil made from cannabis
  - 1500 BC - Earliest written reference to medical marijuana in Chinese pharmacopeia
  - 1213 BC - Egyptians use cannabis for glaucoma, inflammation, and enemas
  - 1000 BC - Bhang, a drink of cannabis and milk, is used in India as an anesthetic
  - 700 BC - Medical use of marijuana in the Middle East recorded in the Venidad
  - 600 BC - Indian medicine treatise cites cannabis as a cure for leprosy
  - 200 BC - Medical cannabis used in Ancient Greece
  - 1 AD - Ancient Chinese text recommends marijuana for more than 100 ailments
  - 30 - Jesus allegedly uses anointing oil made with cannabis
  - 70 - Roman medical text cites cannabis to treat earaches and suppress sexual longing
  - 79 - Pliny the Elder writes about medicinal properties of cannabis plant
  - 200 - Chinese surgeon Hua T’o uses cannabis resin and wine as anesthetic
  - 800-900 - Cannabis used as medicine in Arabic world by some, labeled “Lethal Poison” by others
  - 1500 - Muslim doctors use marijuana to reduce sexuality
  - 1538 - Hemp used during Middle Ages
  - 1578 - Chinese medical text describes medical uses for marijuana
- 1600-1899
  - 1600s - William Shakespeare may have smoked cannabis
  - 1611-1762 - Jamestown settlers bring marijuana to North America
  - 1621 - Popular English mental health book recommends cannabis to treat depression
  - 1652 - Herbalist Nicholas Culpeper writes about medical uses for hemp
  - 1745-1775 - George Washington grows hemp
  - 1774-1824 - Thomas Jefferson grows hemp at Monticello
  - 1799 - Napoleon’s forces bring marijuana from Egypt to France
  - 1840 - Medical marijuana comes to United Kingdom via William O’Shaughnessy and reportedly used by Queen Victoria for menstrual cramps
  - 1840s - Marijuana becomes mainstream medicine in the West
  - 1850 - Marijuana added to U.S. Pharmacopeia
  - 1889 - Article in The Lancet outlines use of cannabis for opium withdrawal
  - 1893-1894 - Indian Hemp Commission mentions several medical uses of cannabis
- 1900-1949
  - 1900 - Cannabis used for asthma, bronchitis, and loss of appetite in South Asia
  - 1906 - Pure Food and Drugs Act requires labeling of medicine, including cannabis
  - 1911 - Massachusetts becomes first state to outlaw cannabis
  - January 1915 - President Wilson signs Harrison Act, the model for future drug regulation legislation
  - 1915-1927 - 10 states pass marijuana prohibition laws
  - 1918 - U.S. pharmaceutical farms grow 60,000 pounds of cannabis annually
  - February 19, 1925 - League of Nations sign multilateral treaty restricting cannabis use to scientific and medical only
  - 1928 - Cannabis added to the UK’s “Dangerous Drugs Act”
  - 1930s - Use of the word “marijuana” increases in the U.S.
  - 1930s - American pharmaceutical firms sell extracts of marijuana as medicines
  - 1930 - Harry J. Anslinger appointed commissioner of the Federal Bureau of Narcotics
  - 1933 - William Randolph Hearst plays role in denouncing marijuana
  - 1936 - Bureau of Narcotics urges federal action to control marijuana
  - 1936 - New medications supplant marijuana as treatment for pain
  - 1936 - Reefer Madness: Film cautions against marijuana
  - May 4, 1937 - American Medical Association opposes the proposed Marihuana Tax Act and supports research on medical cannabis
  - October 1937 - “Marihuana Tax Act” leads to decline in marijuana prescriptions
  - October 2, 1937 - First marijuana seller convicted under U.S. federal law is arrested
  - 1938 - Canada prohibits cannabis cultivation
  - 1942 - Marijuana removed from U.S. Pharmacopeia
  - 1938-1944 - “LaGuardia Report” concludes marijuana less dangerous than commonly thought
- 1950-1969
  - 1951 - Boggs Act establishes minimum prison sentences for simple possession
  - 1956 - Inclusion of marijuana in Narcotics Control Act leads to stricter penalties for marijuana possession
  - 1961 - U.N. convention provides basis for future federal prohibition of marijuana
  - 1964 - THC, the main psychoactive component of cannabis, first identified and synthesized
  - 1968 - University of Mississippi becomes official grower of marijuana for federal government research
  - April 8, 1968 - President Johnson creates Bureau of Narcotics and Dangerous Drugs (BNDD)
  - November 1, 1968 - UK Wootton report finds cannabis is less dangerous than alcohol, other drugs
- 1970-1989
  - 1970 - Controlled Substances Act classifies marijuana as a drug with “no accepted medical use”
  - 1970 - NORML (National Organization for the Reform of Marijuana Laws) founded
  - 1971 - UK introduces drug classification system
  - May 1, 1971 - Nixon says he will not legalize marijuana regardless of any future Shafer Commission recommendations
  - June 17, 1971 - President Nixon declares “War on Drugs”
  - 1972 - National Commission on Marijuana and Drug Abuse (“Shafer Commission”) recommends decriminalizing marijuana
  - 1972 - NORML petitions DEA to reschedule marijuana
  - 1973 - Drug Enforcement Agency (DEA) established
  - 1974 - NIDA established, placed in charge of contracts to grow marijuana for research purposes
  - 1976 - Marijuana decriminalized in the Netherlands
  - November 24, 1976 - Federal court rules Robert Randall’s use of marijuana is a ”medical necessity”
  - 1978 - Federal government compassionate use program supplies patients with marijuana
  - 1978 - New Mexico passes first state law recognizing medical value of marijuana
  - 1980 - Marinol, a synthetic version of THC, and smoked marijuana tested on cancer patients
  - 1981 - Legal medical marijuana patients form organization to help others obtain access
  - 1981-1985 - U.S. government sells Marinol patent to Unimed
  - May 1985 - Marinol approved by FDA
  - 1986 - Anti-Drug Abuse Act increases penalties for marijuana possession and dealing
  - September 6, 1988 - DEA Judge Francis Young recommends marijuana be placed in Schedule II
  - December 30, 1989 - DEA administrator overrules Francis Young and orders that cannabis remain a Schedule I controlled substance
- 1990-1999
  - 1990 - Scientists discover cannabinoid receptors
  - 1991 - Court ruling highlights application of medical necessity defense
  - June 1991 - Federal government suspends IND Compassionate Use Medical Marijuana Program
  - July 1991 - 53 percent of oncologists surveyed say cannabis should be available by prescription
  - November 5, 1991 - First medical marijuana initiative passed in San Francisco
  - 1992 - Scientists discover first endocannabinoid
  - March 19, 1992 - IND Compassionate Use Program officially terminated; 13 existing patients continue to get government marijuana
  - March 1993 - American Medical Student Association unanimously endorses rescheduling of marijuana
  - February 18, 1994 - Final decision in 1972 court battle over marijuana rescheduling keeps marijuana in Schedule I
  - Mid-July 1994 - Assistant secretary of health announces final decision not to reopen IND Compassionate Use Medical Marijuana Program
  - July 10, 1995 - Second petition to reschedule marijuana filed
  - November 5, 1996 - California becomes first state to legalize medical marijuana
  - January 30, 1997 - New England Journal of Medicine publishes editorial calling for marijuana to be rescheduled
  - February 19 and 20, 1997 - NIH says more study needed to assess potential of medical marijuana
  - September 1998 - Congress prevents implementation of medical marijuana law in DC
  - October 29, 1998 - Presidents Ford, Carter, and Bush urge voters to reject medical marijuana
  - November 3, 1998 - Alaska, Oregon, and Washington become 2nd, 3rd, and 4th states to legalize medical marijuana
  - November 11, 1998 - U.K. House of Lords committee recommends legalizing medical marijuana
  - January 1997-March 1999 - Institute of Medicine (IOM) conducts comprehensive study on medical effects of marijuana
  - June 2, 1999 - Alaska makes enrollment in state patient registry mandatory
  - July 1999 - Marinol moved to Schedule III to increase availability to patients
  - August 1999 - Health Canada announces funding for medical research on marijuana
  - November 2, 1999 - Maine becomes fifth state to legalize medical marijuana
- 2000-2004
  - June 14, 2000 - Hawaii becomes sixth state to legalize medical marijuana
  - November 7, 2000 - Colorado and Nevada become seventh and eighth states to legalize medical marijuana
  - May 14, 2001 - Supreme Court rules “there is no medical necessity exception to the Controlled Substances Act”
  - October 1, 2001 - Nevada medical marijuana law amended to create state registry
  - January 2002 - Only study on IND patients finds that medical marijuana improves their quality of life
  - September 2002 - DC court blocks proposed medical marijuana initiative
  - October 29, 2002 - Court rules in Conant v. Walters that government cannot revoke physician licenses solely for recommending medical marijuana
  - July 23, 2003 - U.S. House of Representatives rejects amendment to stop federal raids on medical marijuana patients
  - August 26, 2003 - First Canadian patient to receive government-grown marijuana
  - September 1, 2003 - Dutch pharmacies to supply medical marijuana
  - October 7, 2003 - U.S. government receives cannabinoids patent
  - 2004 - U.K. moves cannabis to Class C, with lower penalties
  - January 1, 2004 - California places limits on medical marijuana possession
  - August 5, 2004 - DEA instructs HHS to review marijuana for possible rescheduling
  - November 2, 2004 - Montana becomes 10th state to legalize medical marijuana
  - December 18, 2004 - AARP poll finds that 72 percent of seniors support medical marijuana
  - May 26, 2004 - Vermont becomes ninth state to legalize medical marijuana
- 2005-2009
  - June 6, 2005 - U.S. Supreme Court rules Congress may ban marijuana use in Gonzalez v. Raich
  - July 8 - July 18, 2005 - California suspends then resumes medical marijuana ID card program
  - December 12, 2005 - Federal agents execute widespread raid on medical marijuana dispensaries in California
  - January 1, 2006 - Oregon’s medical marijuana law amended to exclude affirmative defense for exceeding possession Limits
  - January 3, 2006 - Rhode Island becomes 11th state to legalize medical marijuana after legislature overrides governor’s veto
  - March 16, 2006 - DEA busts marijuana-laced candy manufacturers
  - April 20, 2006 - FDA confirms opposition to smoked marijuana for medical purposes
  - June 21, 2006 - Presbyterian Church approves resolution to support medical marijuana
  - February 12, 2007 - DEA administrative law judge recommends allowing new source of marijuana for research
  - March 13, 2007 - New Mexico becomes 12th state to legalize medical marijuana
  - February 15, 2008 - Nation’s 2nd largest physician group calls for marijuana reclassification and supports monsmoked forms of medical marijuana
  - May 2008 - Cannabis returned to Class B in the U.K.
  - May 22, 2008 - California court rules possession limits on medical marijuana unconstitutional
  - August 25, 2008 - California attorney general issues state guidelines for medical marijuana
  - September 2008 - Two pounds of cannabis found buried in 2,700-year-old Chinese tomb
  - November 4, 2008 - Michigan becomes 13th state to legalize medical marijuana
  - January 12, 2009 - DEA rejects judge’s ruling to allow new source of marijuana for research
  - February 25, 2009 - U.S. attorney general says raids on medical marijuana clinics will not continue
  - October 19, 2009 - U.S. attorney general announces that DOJ will not prioritize prosecution of legal medical marijuana patients
  - November 3, 2009 - Maine’s medical marijuana law amended to provide for dispensaries
  - November 10, 2009 - AMA softens position on scheduling of marijuana
- 2010-2015
  - January 11, 2010 - New Jersey becomes 14th state to legalize medical marijuana
  - January 21, 2010 - California Supreme Court affirms ruling that possession limits are unconstitutional
  - February 17, 2010 - Iowa Board of Pharmacy recommends rescheduling of marijuana
  - April 1, 2010 - Washington expands list of medical professionals authorized to recommend medical marijuana
  - June 4, 2010 - Judge rules against Los Angeles marijuana dispensaries
  - June 7, 2010 - Colorado increases oversight of medical marijuana dispensaries and physician recommendations
  - July 27, 2010 - U.S. Department of Veterans Affairs relaxes marijuana rules for vets
  - July 27, 2010 - Medical marijuana becomes legal in DC
  - November 2, 2010 - South Dakota voters reject medical marijuana measure
  - November 2, 2010 - Arizona becomes 15th state to legalize medical marijuana
  - March 1, 2011 - DEA moves five synthetic cannabinoids into Schedule I, citing “Imminent Hazard”
  - May 13, 2011 - Delaware becomes 16th state to legalize medical marijuana
  - March 23 - May 16, 2011 - U.S. attorneys send threatening letters to states with legal medical marijuana
  - July 1, 2011 - Montana law requiring state residency to become a medical marijuana patient takes effect
  - July 8, 2011 - DEA denies 2002 request to reclassify marijuana out of restrictive Schedule I category
  - August 7, 2011 - Israeli government arranges to supply medical marijuana
  - August 8, 2011 - DEA again rejects Craker’s application to grow marijuana for government
  - November 2011 - Study finds legal medical marijuana reduces fatal car accidents
  - December 1, 2011 - Medical marijuana reclassification sought by Washington and Rhode Island governors
  - February 28, 2012 - Federal judge dismisses lawsuit against government for raids on medical marijuana clinics
  - May 11, 2012 - U.S. Court of Appeals hears oral arguments in Lyle Craker’s federal lawsuit against the DEA
  - May 31, 2012 - Connecticut becomes 17th state to legalize medical marijuana
  - July 24, 2012 - LA City Council bans medical marijuana dispensaries in unanimous vote
  - October 16, 2012 - Federal court hears case to change Schedule I status of marijuana
  - November 6, 2012 - Massachusetts becomes 18th state to legalize medical marijuana
  - January 22, 2013 - U.S. Appeals Court denies medical marijuana reclassification challenge
  - July 23, 2013 - New Hampshire becomes 19th state to legalize medical marijuana
  - August 1, 2013 - Illinois becomes 20th state to legalize medical marijuana
  - August 8, 2013 - Dr. Sanjay Gupta comes out in favor of medical marijuana
  - August 29, 2013 - Justice Department will not challenge state marijuana laws
  - February 14, 2014 - New federal guidelines allow banks to provide financial services to legal marijuana sellers
  - April 14, 2014 - Maryland becomes 21st state to legalize medical marijuana
  - May 29, 2014 - Minnesota becomes 22nd state to legalize medical marijuana
  - July 5, 2014 - New York becomes 23rd state to legalize medical marijuana
  - October 28, 2014 - U.S. Justice Department will not enforce federal marijuana laws on Native American reservations
  - December 17, 2014 - New law bans Justice Department from using funds against medical marijuana in legal states
  - May 3, 2015 - Governor of Puerto Rico legalizes medical marijuana
  - June 22, 2015 - Federal government removes obstacle to marijuana research
- 2016-present
  - April 4, 2016 - DEA considers moving marijuana to less-restrictive drug schedule
  - April 18, 2016 - Pennsylvania becomes 24th U.S. state to legalize medical marijuana
  - June 8, 2016 - Ohio becomes 25th U.S. state to legalize medical marijuana
  - August 11, 2016 - DEA declines to reschedule marijuana but opens door to research
  - November 8, 2016 - Arkansas, Florida, North Dakota vote to legalize medical marijuana
  - April 19, 2017 - West Virginia becomes 29th U.S. state to legalize medical marijuana
  - June 19, 2017 - Mexico legalizes medical marijuana
  - January 4, 2018 - U.S. Attorney General ends Obama-era marijuana guidelines
  - June 25, 2018 - FDA approves first marijuana-based drug
  - June 26, 2018 - Oklahoma becomes 30th U.S. state to legalize medical marijuana
  - December 20, 2018 - President Trump signs bill legalizing industrial hemp
  - December 25, 2018 - Thailand legalizes medical marijuana
  - September 19, 2019 - U.S. government allocates $3 million for research on CBD and pain
  - November 3, 2020 - Mississippi and South Dakota legalize medical marijuana
  - December 2, 2020 - United Nations commission reclassifies medical marijuana
  - December 4, 2020 - U.S. House passes marijuana decriminalization bill
  - May 14, 2021 - Mississippi medical marijuana effort thwarted by outdated constitutional requirement
  - May 14, 2021 - DEA to allow more domestic sources for cannabis research
  - July 16, 2021 - New study: Cannabis likely originated in northwest China
  - February 2, 2022 - Mississippi 37th state to legalize medical marijuana
  - April 1, 2022 - U.S. House passes bill to decriminalize marijuana
  - May 8, 2022 - Thai government to give away one million free cannabis plants in June 2022
  - October 6, 2022 - President Biden pardons thousands with federal marijuana possession convictions
  - March 2023 - “Father of cannabis research” Raphael Mechoulam dies
  - March 31, 2023 - Kentucky legalizes medical marijuana
  - August 29, 2023 - HHS recommends rescheduling marijuana
  - Jan 28, 2025 - Largest study to date connects cannabis use and difficulty with memory tasks
  - December 18, 2025 - Trump orders rescheduling process for marijuana
  - April 23, 2026 - Some marijuana products federally rescheduled
Assessment quiz
1-minute survey
Discussion questions
Sources

References & Edit History Related Topics

Images

Medical marijuana

Close-up of green, serrated marijuana leaves on a plant growing outdoors.

A full page of ancient Egyptian writing in black and some red ink.

The Anatomy of Melancholy

Queen Victoria and Prince Albert with five of their nine children.

President Richard Nixon and Elvis Presley

A woman wearing glasses and a straw hat exhales smoke while holding a joint, standing among tall cannabis plants in an outdoor plantation.

Map of the United States displaying the legal status of marijuana by state as of late 2024. States where marijuana is legal for adult use are shaded green, states where it is illegal are shaded orange, and states with conditionally decriminalized possession are marked with a lighter orange. Additional symbols indicate where marijuana is legal for medicinal use or where only low-THC medicinal use is permitted.

Medical marijuana: References & Edit History

Article Contributors

Primary Contributors

The Editors of ProCon
ProCon's editors write and verify new content and update existing content. ProCon presents the pro and con arguments to debatable issues in a straightforward, nonpartisan, freely accessible way.

Other Encyclopedia Britannica Contributors

Emily Rodriguez

Article History

Type	Description	Contributor	Date
	Discussion questions standardized.	The Editors of ProCon	Jul 23, 2026
	Rescheduling of some marijuana products added.	The Editors of ProCon	Apr 23, 2026
	Missing period added.	The Editors of ProCon	Feb 28, 2026
	Quote added.	The Editors of ProCon	Feb 28, 2026
	Reference fixed.	The Editors of ProCon	Feb 27, 2026
	Overall update.	The Editors of ProCon	Feb 27, 2026
	Photo added.	The Editors of ProCon	Feb 04, 2026
	Quiz added.	The Editors of ProCon	Jan 22, 2026
	Introduction expanded.	The Editors of ProCon	Jan 04, 2026
	Introduction expanded.	The Editors of ProCon	Jan 04, 2026
	Trump rescheduling executive order added.	The Editors of ProCon	Dec 19, 2025
	Recent study added.	The Editors of ProCon	Dec 16, 2025
	November 2025 medical study added.	The Editors of ProCon	Dec 15, 2025
	Images of Surgeons General added.	The Editors of ProCon	Aug 07, 2025
	Photos and marijuana studies section added.	The Editors of ProCon	Jul 29, 2025
	Invalidated site: Verywell Health - Pros and Cons of Legalizing Marijuana.	Emily Rodriguez	May 22, 2025
	Survey added.	The Editors of ProCon	May 06, 2025
	Add new Web site: Verywell Health - Pros and Cons of Legalizing Marijuana.	Emily Rodriguez	Mar 18, 2025
	Typo fixed.	The Editors of ProCon	Feb 10, 2025
	Text updated.	The Editors of ProCon	Feb 10, 2025
	Link adjusted.	The Editors of ProCon	Feb 05, 2025
	Link added.	The Editors of ProCon	Feb 05, 2025
	Links added, text clarified.	The Editors of ProCon	Jan 08, 2025
	New article added.	The Editors of ProCon	Nov 08, 2024