This article contains a timeline of significant events regarding psychedelic drugs and their legalization and decriminalization for personal, religious, and/or medical use. Major psychedelics include LSD, psilocybin, mescaline, dimethyltryptamine (DMT), 5-MeO-DMT, and 2C-B. Some of these psychedelics are naturally occurring in plants, fungi, and animals, for instance in psilocybin-containing mushrooms, ayahuasca, peyote, and Sonoran Desert toad venom. This timeline also includes MDMA, which is closely related to psychedelics, but not other types of hallucinogens like ketamine, ibogaine, or cannabis.

1600s 1617 Spanish colonialists broadly ban the use of various hallucinogens in Mexico.

1620 Spanish colonialists more specifically ban the use of peyote in Mexico.

1800s 1899 Oklahoma passes the first law banning peyote as part of anti-Native American sentiment, but the law is repealed a decade later.

1910s 1916 Three anti-peyote laws are introduced into Congress in the United States between 1916 and 1918 as part of anti-Native American sentiment but fail to pass.

1930s 1930 More than a dozen states in the United States ban possession of peyote as part of anti-Native American sentiment.

1937 Most states in the United States west of the Mississippi River have laws restricting peyote.

1960s 1962 The Kefauver–Harris Amendment is passed in the United States and research and sales of experimental drugs including psychedelics are thereby restricted.

1963 Psychedelics first discussed by a United Nations drug policy body.Eighteenth session of the Commission on Narcotic Drugs within the United Nations Economic and Social Council. Summary record of the five hundred and eighteenth meeting (Verbatim Records No. E/CN.7/SR.518).

1965 Psychedelics are banned in New York.

1966 Psychedelics like LSD are banned in California and certain other states. LSD is banned in the United Kingdom. The Commission on Narcotic Drugs (CND) within the United Nations recommended global control of psychedelics.Questions relating to the Control of Substances not under International Control. Report of the Committee on Substances not under International Control. Note by the Secretary-General (No. E/CN.7/ AC.6/8). United Nations

1967 Both the World Health Organization (WHO)World Health Assembly, 20 (1967). Control measures for LSD and related substances. World Health Organization. https://iris.who.int/handle/10665/89509 and United Nations Economic and Social Council (ECOSOC)UN. (1967c). Economic and Social Council. (16 May 1967). LSD and similar substances. E/RES/1197(XLII) issue resolutions recommending all nations to ban psychedelics.

1968 The Staggers–Dodd Bill criminalizes LSD and psilocybin in the United States, but was not heavily enforced. LSD and dimethyltryptamine (DMT) are banned in Canada.

1969 The World Health Organization (WHO) suggested that the new international drug treaty by the United Nations would aptly control psychedelics in Schedule I. World Health Organization. Expert Committee on Drug Dependence: Eighteenth report (No. 460). World Health Organization.

1970s 1970 The Comprehensive Drug Abuse Prevention and Control Act of 1970 bans psychedelics including LSD, psilocybin, psilocin, mescaline, peyote, dimethyltryptamine (DMT), and MDA in the United States, placing them in Schedule I.

1971 The Convention on Psychotropic Substances by the United Nations bans psychedelics including LSD, dimethyltryptamine (DMT), mescaline, psilocybin, and psilocin among others internationally. The Misuse of Drugs Act 1971 bans psychedelics including LSD, dimethyltryptamine (DMT), mescaline, psilocybin, and psilocin among others in the United Kingdom. 5-MeO-DMT is also banned as an ether of bufotenin.

1974 Canada bans psilocybin. The Supreme Court of Spain decriminalizes possession of small amounts of drugs, including psychedelics. Uruguay legalizes possession of small amounts of drugs, including psychedelics.

1977 The United Kingdom introduces structural blanket bans that ban many psychedelics including MDA, MDMA, and 2C-B among others.

1978 Congress in the United States passes the American Indian Religious Freedom Act, which enshrines protections for Native American religious practices including peyote use and possession.

1979 The Native American Church of New York (renamed to the Temple of the True Inner Light in 1980 and not actually Native American) sues for the right to use various psychedelics for religious purposes in the United States but largely loses the case. Supplemental Video "The Native American Church of New York existed for a little over three years in the late 1970s. It had no affiliation with the federally recognized Native American Church of America and was not founded by Native Americans. Additionally, it counted no Native Americans among its members. After the arrest of its leader in 1979, The Native American Church of New York changed their name to The Temple of the True Inner Light."

1980s 1982 Spain formally decriminalizes possession of small amounts of drugs, including psychedelics.

1985 MDMA is banned and placed in Schedule I in the United States.

1986 The United Nations bans MDMA internationally. The United States passes the Federal Analogue Act, banning designer drugs structurally similar to existing controlled substances, including psychedelics. The Multidisciplinary Association for Psychedelic Studies (MAPS) is founded by Rick Doblin in response to the United States banning MDMA, with the aim of working towards legal therapeutic use of psychedelics. Brazil legalizes the use of ayahuasca for religious purposes.

1988 Switzerland legalizes limited use of LSD and MDMA in therapeutic settings.

1990s 1990 The United States Supreme Court rules that use and possession of peyote for religious purposes is illegal, overriding Congress. Czech Republic (Czechia) decriminalizes possession of small amounts of drugs, including psychedelics.

1992 Brazil permanently legalizes the use of ayahuasca for religious purposes.

1993 Congress in the United States passes the Religious Freedom Restoration Act to reverse the 1990 Supreme Court ruling on peyote religious legality. Switzerland ends legal use of LSD and MDMA in therapeutic settings.

1994 Congress in the United States passes the American Indian Religious Freedom Act Amendments of 1994, which explicitly legalizes use and possession of peyote for Native American religious practices. Colombia decriminalizes possession of drugs, including psychedelics.

1995 2C-B is banned and placed in Schedule I in the United States.

1996 Canada passes the Controlled Drugs and Substances Act (CDSA) and places psychedelics, including LSD and psilocybin, in Schedule III.

2000s 2001 Portugal decriminalizes personal possession of all drugs, including psychedelics. The United Nations bans 2C-B internationally.

2005 Chile decriminalizes possession of small amounts of drugs for personal use, including psychedelics. The United Kingdom bans psilocybin-containing mushrooms, which had been legal in the country due to a legal loophole.

2006 The United States Supreme Court rules that the União do Vegetal (UDV) can legally import and use ayahuasca for religious purposes.

2008 Peru legalizes the use of ayahuasca for religious purposes. The Netherlands bans psilocybin-containing mushrooms, though "magic truffles" remain unaffected.

2009 A federal court in the United States rules that the Church of the Holy Light of the Queen, a Santo Daime church, can legally import and use ayahuasca for religious purposes. Argentina decriminalizes possession of psychedelics, though the legal situation remains mixed. Mexico decriminalizes possession of small amounts of drugs including LSD, MDA, and MDMA.

2010s 2010 The Czech Republic decriminalizes possession of small amounts of psychedelics including psilocybin, LSD, MDMA, and peyote.

2011 5-MeO-DMT is banned and placed in Schedule I in the United States.

2012 Croatia decriminalizes possession of small amounts of drugs, including psychedelics.

2013 New Zealand passes the Psychoactive Substances Act, allowing government-licensed sale of psychoactive drugs including psychedelics.

2014 New Zealand passes the Psychoactive Substances Amendment Act, effectively reversing much of the 2013 act. Switzerland once again legalizes medical use of certain psychedelics including LSD, psilocybin, and MDMA. Flor da Mãe Divina (Flower of the Divine Mother), a Santo Daime church in California, applies for and obtains a permit from the Drug Enforcement Administration (DEA) to legally use ayahuasca for religious purposes.

2016 Austria decriminalizes drug possession for personal use including psychedelics.

2017 The United States Food and Drug Administration (FDA) designates MDMA-assisted therapy for treatment of post-traumatic stress disorder (PTSD) as a breakthrough therapy.

2018 The United States Food and Drug Administration (FDA) designates psilocybin for treatment-resistant depression (TRD) as a breakthrough therapy.

2019 Decriminalize Nature is founded in the United States and starts campaigning for decriminalization of naturally occurring entheogens. Denver, Colorado votes to decriminalize psilocybin-containing mushrooms, becoming the first city in the United States to do so. Oakland, California votes to decriminalize plants and fungi containing psychedelics including dimethyltryptamine (DMT), mescaline, and psilocybin following campaigning by Decriminalize Nature. Israel approves compassionate use program of MDMA for post-traumatic stress disorder (PTSD) in medical settings, becoming the first country in the world to do so. The United States Food and Drug Administration (FDA) designates psilocybin for major depressive disorder (MDD) as a breakthrough therapy.

2020s 2020 Santa Cruz, California votes to decriminalize psychedelics including psilocybin, ayahuasca, and peyote. Ann Arbor, Michigan decriminalizes all naturally occurring psychedelics, including psilocybin, ayahuasca, and peyote among others. Washington, D.C. decriminalizes naturally occurring psychedelic plants and fungi, including psilocybin, ayahuasca, and peyote. Oregon decriminalizes possession of small amounts of drugs including psychedelics and creates a legal psilocybin therapy framework, becoming the first state in the United States to do either of these things.

2021 California Senate approves bill to decriminalize several major psychedelics. Seattle, Washington decriminalizes psilocybin-containing mushrooms, ayahuasca, and non-peyote-derived mescaline. Oregon's bill decriminalizing drugs including psychedelics takes effect. Several Massachusetts cities, including Somerville, Cambridge, Northampton, and Easthampton, pass measures deprioritizing or decriminalizing natural psychedelics. Detroit, Michigan decriminalizes psychedelic plants and fungi including psilocybin-containing mushrooms.

2022 San Francisco, California decriminalizes psychedelic plants and fungi, including psilocybin, mescaline, and dimethyltryptamine (DMT) among others. Colorado decriminalizes dimethyltryptamine (DMT), mescaline (excluding peyote), psilocybin, and psilocin and becomes the second state in the United States to enact a regulated psychedelic therapy program. Canada adds psychedelics including psilocybin, MDMA, dimethyltryptamine (DMT), LSD, and others to its special access program for medical use. Thailand begins studying psilocybin-containing mushrooms for therapeutic purposes and hints at further drug law reform. The United States Drug Enforcement Administration (DEA) proposes scheduling five more-obscure psychedelics including 4-HO-DiPT, 5-MeO-AMT, 5-MeO-MiPT, 5-MeO-DET, and DiPT as Schedule I controlled substances. The psychedelic community prominently challenges and opposes the proposal and the DEA soon withdraws it.

2023