Ayahuasca[note 1] is a South American psychoactive beverage, traditionally used by Indigenous cultures and folk healers in the Amazon and Orinoco basins for spiritual ceremonies, divination, and healing a variety of psychosomatic complaints.

[1] Originally restricted to areas of Peru, Brazil, Colombia and Ecuador, in the middle of the 20th century it became widespread in Brazil in the context of the appearance of syncretic religions that use ayahuasca as a sacrament, like Santo Daime, União do Vegetal and Barquinha, which blend elements of Amazonian Shamanism, Christianity, Kardecist Spiritism, and African-Brazilian religions such as Umbanda, Candomblé and Tambor de Mina, later expanding to several countries across all continents, notably the United States and Western Europe, and, more incipiently, in Eastern Europe, South Africa, Australia, and Japan.

[2][3][4] More recently, new phenomena regarding ayahuasca use have evolved and moved to urban centers in North America and Europe, with the emergence of neoshamanic hybrid rituals and spiritual and recreational drug tourism.

[13] Ayahuasca is a hallucinogen commonly made by the prolonged decoction of the stems of the Banisteriopsis caapi vine and the leaves of the Psychotria viridis shrub, although hundreds of species are used in addition or substitution (See "Preparation" below).

Although orally inactive, B. caapi is rich with harmala alkaloids, such as harmine, harmaline and tetrahydroharmine (THH), which can act as monoamine oxidase inhibitors (MAOi).

This halts the liver and gastrointestinal metabolism of DMT, allowing it to reach the systemic circulation and the brain, where it activates 5-HT1A/2A/2C receptors in frontal and paralimbic areas.

Although ayahuasca is the most widely used term in Peru, Bolivia, Ecuador and Brazil, the brew is known by many names throughout northern South America: In the last decades, two new important terminologies emerged.

Both are commonly used in the Western world in neoshamanic, recreative or pharmaceutical contexts to address ayahuasca-like substances created without the traditional botanical species, due to it being expensive and/or hard to find in these countries.

These concepts are surrounded by some controversies involving ethnobotany, patents, commodification and biopiracy:[38][39][40] Archaeological evidence of the use of psychoactive plants in northeastern Amazon dates back to 1500–2000 BCE.

Despite claims by numerous anthropologists and ethnologists, such as Plutarco Naranjo,[47] regarding the millennial usage of ayahuasca, compelling evidence substantiating its pre-Columbian consumption is yet to be firmly established.

[48] Jose Chantre y Herrera still in the seventeenth century, provided the first detailed description of a "devilish potion" cooked from bitter herbs and lianas (called ayaguasca) and its rituals:[49] "[...] In other nations, they set aside an entire night for divination.

So, the person who wants to divine drinks the chosen substance with certain rituals, and while deprived of their senses from the mouth downwards, to prevent the strength of the plant from harming them, they remain in this state for many hours and sometimes even two or three days until the effects run their course, and the intoxication subsides.

[54] In academic discourse, the initial mention of ayahuasca dates back to Manuel Villavicencio's 1858 book, "Geografía de la República del Ecuador."

[68][53] Indeed, the colonial processes in Western Amazon are intrinsically related with the development of ayahuasca use in the last three centuries, as it promoted a deep reshape in traditional ways of life in the region.

As a result, the ayahuasca shamans in urban areas and mestizo settlements, specially in the regions of Iquitos and Pucallpa (in Peru), became the vegetalistas, folk healers who are said to gain all their knowledge from the plants and the spirits bound to it.

In the end of the nineteenth century, several messianic/millennialist cults sparkled across semi-urban areas across the entire Amazon region, merging different elements of indigenous and mestizo folk culture with Catholicism, Spiritism and Protestantism.

[70][71] In this context, the use of ayahuasca will take form of urban, organized non-indigenous religions in outskirts of main cities of northwest of Brazil, (along the basins of Madeira, Juruá and Purus River)[72] within the cauchero/seringueiro cultural complex, resignifying and adapting both the vegetalista and mestizo shamanism to new urban formations, unifying essential elements to building a cosmology for the new emerging cult/faith, merging with elements of folk Catholicism, African-Brazilian religions and Kardecist spiritism.

These new cults arise from charismatic leaderships, often messianic and prophetic, who came from rural areas after migration movements, sometimes called ayahuasqueiros, in semi-urban communities across the borders of Brazil, Bolívia and Peru (a region that will later form the state of Acre).

[76] Beat writer William S. Burroughs read a paper by Richard Evans Schultes on the subject and while traveling through South America in the early 1950s sought out ayahuasca in the hopes that it could relieve or cure opiate addiction (see The Yage Letters).

Richard Evans Schultes allowed Claudio Naranjo to make a special journey by canoe up the Amazon River to study ayahuasca with the South American Indians.

[84] Sections of Banisteriopsis caapi vine are macerated and boiled alone or with leaves from any of a number of other plants, including Psychotria viridis (chacruna), Diplopterys cabrerana (also known as chaliponga and chacropanga),[85] and Mimosa tenuiflora, among other ingredients which can vary greatly from one shaman to the next.

This brew varies radically from one batch to the next, both in potency and psychoactive effect, based mainly on the skill of the shaman or brewer, as well as other admixtures sometimes added and the intent of the ceremony.

Bogers and Fijneman were charged with distributing a controlled substance (DMT); however, the prosecution was unable to prove that the use of ayahuasca by members of the Santo Daime constituted a sufficient threat to public health and order such that it warranted denying their rights to religious freedom under ECHR Article 9.

[13] People who have consumed ayahuasca report having mystical experiences and spiritual revelations regarding their purpose on earth, the true nature of the universe, and deep insight into how to be the best person they possibly can.

[89] However, at least in Iquitos, Peru (a center of ayahuasca ceremonies), those from the area describe the experiences more in terms of the actions in the body and understand the visions as reflections of their environment, sometimes including the person who they believe caused their illness, as well as interactions with spirits.

Neither the crown (fruit, mescal button) of the Peyote cactus nor the roots of the plant Mimosa hostilis nor Psilocybe mushrooms themselves are included in Schedule 1, but only their respective principals, mescaline, DMT, and psilocin.

This recommendation by the INCB has been criticized as an attempt by the Board to overstep its legitimate mandate and as establishing a reason for governments to violate the human rights (i.e., religious freedom) of ceremonial ayahuasca drinkers.

In March 2009, U.S. District Court Judge Panner ruled in favor of the Santo Daime, acknowledging its protection from prosecution under the Religious Freedom Restoration Act.

The City Council passed the resolution in a unanimous vote, ending the investigation and imposition of criminal penalties for use and possession of entheogens derived from plants or fungi.

In 1999 they brought a legal challenge to this patent which had granted a private US citizen "ownership" of the knowledge of a plant that is well-known and sacred to many Indigenous peoples of the Amazon, and used by them in religious and healing ceremonies.