Ayahuasca is made from two primary plants: a woody vine called Banisteriopsis caapi and the leaves of Psychotria viridis, a shrub native to the Amazon. The vine and leaves are boiled together in water for hours to produce a thick, bitter tea. What makes this combination remarkable is that neither plant produces strong psychoactive effects on its own when swallowed. The two work together through a specific chemical interaction that indigenous Amazonian peoples discovered centuries ago.
The Two Core Plants
Banisteriopsis caapi is a large jungle vine from the Malpighiaceae family, native to the Amazon and Orinoco river basins. In traditional settings it’s called “the vine of the soul,” and it forms the base of every ayahuasca brew. The vine’s bark contains three key compounds: harmine, harmaline, and tetrahydroharmine. These belong to a class of chemicals that temporarily block an enzyme in your gut and liver called monoamine oxidase-A (MAO-A).
Psychotria viridis, commonly called chacruna, is a leafy shrub whose leaves contain DMT (N,N-dimethyltryptamine), one of the most potent naturally occurring psychedelics. DMT concentration in the leaves ranges from 0.1% to 0.66% of dry weight. On its own, DMT is inactive when swallowed because your body’s MAO enzymes break it down almost instantly in the digestive tract.
Why Both Plants Are Needed
This is the central puzzle of ayahuasca, and the reason the brew works at all. DMT from the chacruna leaves would normally be destroyed in your gut before reaching your bloodstream. But the vine’s compounds act as MAO inhibitors, temporarily shutting down the enzyme that would break DMT apart. With that enzyme blocked, DMT passes through the stomach and intestines intact, enters the bloodstream, and reaches the brain, where it activates serotonin receptors and produces intense visionary effects.
How indigenous peoples arrived at this specific pairing, out of roughly 80,000 plant species in the Amazon, remains one of ethnobotany’s most discussed questions. The Shuar, Kichwa, and other Amazonian groups have used the brew for spiritual and healing purposes, with archaeological evidence of psychoactive plant use in the region dating back to at least 900 B.C. among the Chavín people of Peru.
What’s Actually in a Typical Dose
The alkaloid content of ayahuasca varies enormously depending on the plants used, how long the brew is cooked, and regional preparation traditions. Chemical analyses of different preparations show just how wide the range can be. A 100 mL dose from one Brazilian religious group (the União do Vegetal) contained about 170 mg of harmine, 107 mg of tetrahydroharmine, 20 mg of harmaline, and 24 mg of DMT. Samples analyzed from Pucallpa, Peru, contained far more: 467 mg of harmine, 160 mg of tetrahydroharmine, 41 mg of harmaline, and 60 mg of DMT per 100 mL.
The vine’s compounds consistently make up the bulk of the alkaloid content, often accounting for 80% or more of the total. DMT is present in smaller amounts but is responsible for the characteristic visual and perceptual effects. The vine compounds do more than just protect DMT from breakdown; tetrahydroharmine in particular has its own psychoactive properties, contributing to the sedative, dreamlike quality of the experience.
Other Plants Sometimes Added
While the two-plant combination dominates modern use, traditional preparations across the Amazon have incorporated up to 100 different plant species as additives. Some of the most common alternatives and additions include:
- Diplopterys cabrerana (chaliponga): used as an alternative DMT source in place of chacruna, particularly in parts of Ecuador and Colombia
- Nicotiana species: tobacco leaves, added for their stimulant properties
- Brugmansia species: potent plants containing scopolamine, used by some groups but carrying serious toxicity risks
- Ilex guayusa and Paullinia yoco: caffeine-containing plants sometimes added for alertness
Outside of traditional contexts, some preparations have been found to contain Syrian rue (Peganum harmala) seeds as a substitute for Banisteriopsis caapi. Syrian rue is rich in harmaline and is far easier to obtain globally, but it changes the chemical profile of the brew significantly. Analysts can detect this substitution by measuring the ratio of harmaline to harmine, which skews much higher with Syrian rue than with authentic vine preparations.
How the Brew Is Prepared
Traditional preparation is labor-intensive and can span two full days. The process begins with the vine. Sections of Banisteriopsis caapi are pounded with wooden clubs until the tough, woody braids separate into fine fibers, increasing the surface area for extraction. In one documented preparation at a Santo Daime church in Brazil, each pot received 40 kilograms of pounded vine, 8 kilograms of chacruna leaves, and 60 liters of water.
The mixture is boiled over a wood fire for several hours until the liquid reduces to roughly half its original volume, producing a yellowish-brown liquid. This first extraction is drained off, and the process is repeated. The concentrated liquid from the first two batches is then combined in a third pot with fresh vine and carefully selected leaves, then cooked down again. The degree of reduction determines the brew’s potency. A 5:1 reduction (60 liters down to 12) produces a dark, strong brew used in healing ceremonies. Further concentration to 10:1 yields a viscous, syrupy liquid sometimes called “honey.” Some groups continue reducing to 20:1 or beyond, creating a gel-like concentrate that’s easier to transport.
The finished brew is bottled while still hot to prevent fermentation. In the documented preparation, two days of continuous work produced about 140 liters of finished ayahuasca.
Dangerous Interactions
Because ayahuasca contains MAO inhibitors, it interacts dangerously with a range of common medications and substances. The most serious risk is serotonin syndrome, a potentially fatal condition caused by too much serotonin accumulating in the brain. This can happen when the MAO-blocking compounds in the brew are combined with drugs that also raise serotonin levels.
Antidepressants are the primary concern. SSRIs like fluoxetine, sertraline, citalopram, and escitalopram, along with SNRIs like venlafaxine and desvenlafaxine, all increase serotonin activity and pose a real risk when combined with ayahuasca. Tricyclic antidepressants and other MAO inhibitors are equally dangerous. At least one documented case of serotonin syndrome occurred from the combination of ayahuasca with an SSRI.
Foods high in tyramine, such as aged cheeses, cured meats, and red wine, can also cause problems. Normally, MAO enzymes in your gut break down tyramine before it enters circulation. With those enzymes blocked by the vine’s compounds, tyramine can accumulate and cause a dangerous spike in blood pressure. Recreational drugs including MDMA, LSD, and alcohol also carry unpredictable risks when combined with the brew.
Legal Status
DMT is classified as a Schedule I controlled substance under the U.S. Controlled Substances Act, making ayahuasca illegal by default in most circumstances. Two exceptions exist: branches of the Brazilian religions União do Vegetal and Santo Daime have been granted formal DEA registrations to use ayahuasca in religious ceremonies within the United States, protected under the Religious Freedom Restoration Act. Outside of these specific religious exemptions, possessing or distributing the brew remains a federal offense.