Ayahuasca is a hallucinogenic drink made from the stem of the ayahuasca vine (Banisteriopsis caapi). The ayahuasca drink is sometimes, but rarely, made from the ayahuasca vine alone; almost invariably other plants are added. These additional ingredients are most often the leaves of any of three compañeros, companion plants — the shrub chacruna (Psychotria viridis), the closely related shrub sameruca (Psychotria carthaginensis), or a vine variously called ocoyagé, chalipanga, chagraponga, and huambisa (Diplopterys cabrerana).

Additional plants may be added to this basic two- or three-plant mixture. One report lists 55 different plant species that have reportedly been used as ayahuasca “admixture plants,” and another lists more than 120. Whatever plants the drink may have in addition to ayahuasca, the drink is still called ayahuasca.

The term ayahuasca is in the Quechua language. The word huasca is the usual Quechua term for any species of vine. The word aya refers to something like a separable soul, and thus, also, to the spirit of a dead person — hence the two common English translations, “vine of the soul” and “vine of the dead.” The word ayahuasca can apparently have either connotation, depending largely on cultural context. Quechua speakers in Canelos or on the Napo, as well as the mestizo shamans with whom I have worked, translate the word into Spanish as soga del alma, vine of the soul; people on the Bajo Urubamba often translate the word as soga de muerto, vine of the dead, based on a local association of the jungle generally, and ayahuasca in particular, with a malicious ghost called a bone demon, which seeks to eat people, or kill them through violent sexual intercourse.

The Quechua term ayahuasca is used primarily in present-day Perú and Ecuador; in Colombia the common term for both the vine and the drink is the Tukano term yagé or yajé. There are many additional words for ayahuasca in other indigenous languages; Luis Eduardo Luna has listed 42 of them.

The ritual use of ayahuasca is a common thread linking the religion and spirituality of almost all the indigenous peoples of the Upper Amazon, including the mestizo population; it seems probable that the shamanic practices of most of the Upper Amazon — Brazil, Venezuela, Colombia, Ecuador, Perú, Bolivia — form a single religious culture area. Ayahuasca use is found as far west as the Pacific coastal areas of Panamá, Colombia, and Ecuador; southward into the Peruvian and Bolivian Amazon; among the Indians of Colombia; among the Quichua, Waoroni, Shuar, and other peoples of Ecuador; and in Amazonian Brazil. Luis Eduardo Luna has compiled a bibliography of more than 300 items and has enumerated 72 indigenous groups reported to have used ayahuasca.

This Upper Amazonian religious culture area is characterized by a number of common features — the use of psychoactive plants; the presence of magical substances kept within the shaman’s body; notions of sickness as caused by the intrusion of pathogenic objects projected by an enemy or sorcerer; the ambiguity of shamanic ability to do both good and evil; the central sacrality of tobacco; the acquisition of songs from the spirits; the use of songs for the creation of both medicines and poisons; a focus on healing with the mouth through blowing and sucking; and the importance of sound — singing, whistling, blowing, and rattling — in both healing and sorcery.

The ayahuasca drink has several primary actions: it is a hallucinogen, emetic, purgative, and vermifuge. In fact, there is reason to think that the ayahuasca vine was first used for its emetic, purgative, and vermifuge activities. Even today, the ayahuasca drink is often called, simply, la purga, and used to induce violent vomiting, with hallucinations considered side-effects; indeed, ayahuasqueros are sometimes called purgueros. But the emetic effect of the ayahuasca drink has spiritual resonance as well; vomiting shows that the drinker is being cleansed. La purga misma te enseña, they say; vomiting itself teaches you.

Interestingly, given the emetic effect of the ayahuasca vine, the term used by mestizo shamans to describe the hallucinatory mental state induced by ayahuasca is mareación, from the verb marearse, feel sick, dizzy, nauseous, drunk, seasick. When the ayahuasca has taken hold and one is hallucinating, one is said to be mareado; it is a good thing to be buen mareado after drinking ayahuasca. The term has been extended to include the effects of psychoactive plants such as toé (Brugmansia spp.) which have no emetic effect.

It is undoubtedly harmaline, one of the β-carboline components of the ayahuasca vine, that provides its emetic and purgative properties. Harmaline is also found in Syrian rue (Peganum harmala), from which it was first isolated and after which it was named; like the ayahuasca vine, Syrian rue has been used as an emetic and vermifuge. Doses of harmaline as small as 200 mg orally produce nausea, vomiting, and diarrhea in human volunteers. Five grams of Syrian rue seeds produce mild nausea and vomiting; higher doses produce both vomiting and diarrhea, in some cases serious enough to be incapacitating. These gastrointestinal effects appear to be related to the ability of harmaline to inhibit peripheral monoamine oxidase-A (MAO-A). It also appears that there is habituation to the emetic and purgative activity of harmaline: shamans, who have drunk ayahuasca hundreds or even thousands of times, seldom exhibit its emetic or purgative effects.

Rather, for the shaman, ayahuasca is a teaching plant; it is through the hallucinogenic power of the ayahuasca drink that the hundreds of healing plants, including the plants used for magical attack and defense, reveal their appearance and teach their songs; it is through the power of ayahuasca that the shaman can see distant galaxies and planets, the wellbeing of distant relatives, the location of lost objects, the lover of an unfaithful spouse, and the identity of the sorcerer who has caused a patient to become sick. It is the ayahuasca drink that nurtures the shaman’s phlegm, the physical manifestation of shamanic power within the body, used both as defense against magical attack and as a container for the magic darts that are the shaman’s principal weapon.

It is in fact the companion plant — chacruna or ocoyagé or sameruca — that contains the potent hallucinogen dimethyltryptamine (DMT). But, while DMT is effective when administered parenterally, it is, when taken orally, inactivated by peripheral monoamine oxidase-A (MAO-A), an enzyme found in the lining of the stomach, whose function is precisely to oxidize molecules containing an NH2 amine group, like DMT. There are thus two ways to ingest DMT or plants containing DMT — by parenteral ingestion through nasal inhalation, smoking, or injection; or by mixing the DMT with an MAO inhibitor that prevents the breakdown of DMT in the digestive tract. In fact, that is just what the ayahuasca vine contains — the β-carbolines harmine, harmaline, and tetrahydroharmine, which are potent inhibitors of MAO-A. Combining the ingredients of the ayahuasca drink allows the DMT to produce its hallucinogenic effect when orally ingested — a unique solution which apparently developed only in the Upper Amazon.

It is probably worth noting that the ayahuasca drink tastes awful. It has an oily, bitter taste and viscous consistency that clings to your mouth, with just enough hint of sweetness to make you gag. There are also significant differences between parenterally administered DMT and the ayahuasca drink. The effects of parenterally administered DMT appear with startling rapidity; as one user colorfully put it, “The kaleidoscopic alien express came barreling down the aetheric superhighway and slammed into my pineal.” In addition, these effects are short-lived — not much longer than thirty minutes — which at one time earned DMT the street appellation businessman’s lunch. On the contrary, the effects of the ayahuasca drink appear slowly, even slyly, in thirty to forty minutes, and then last approximately four hours, depending on the strength and constituents of the particular mixture.

Remarkably, while tolerance to the emetic and purgative effects of harmaline develops over time, consistent users of DMT, such as shamans, do not develop tolerance for its hallucinogenic effects.

Steve Beyer’s blog Singing to the Plants is at www.singingtotheplants.blogspot.com