Malpighiaceae
Banisteriopsis caapi
Ayahuasca vine · Yage · Caapi
- Part used
- barkwood
- Native range
- The Amazon basin — Peru, Ecuador, Colombia, Brazil
- Morphology
- A large woody liana climbing high into the canopy, with characteristically twisted and fluted stems and small pink flowers.
What is in it
Evidence
Preliminary research exists on ayahuasca in depression and addiction, mostly small and open-label. Nothing established, and none of it concerns the vine alone.
Safety
The beta-carbolines are monoamine oxidase inhibitors, and that is the central hazard. MAO inhibition creates serious and potentially fatal interactions with a long list of drugs and foods, and it is the reason deaths have occurred in tourist settings. Vomiting and diarrhoea are expected parts of the experience rather than adverse events. Contraindicated in psychosis risk and in cardiac disease.
Interactions: Potentially fatal with SSRIs, SNRIs and other serotonergic drugs; Dangerous with tyramine-containing foods, as with any MAO inhibitor; Interacts with a wide range of medicines through MAO inhibition
Regulatory: Harmine and DMT are controlled in Australia and most jurisdictions. Religious exemptions exist for some churches in Brazil and the United States.
Historical use
Used across the western Amazon in ceremonial contexts by a large number of distinct peoples, each with its own practices, songs and cosmology. The vine is one component of a brew that also requires a DMT-containing plant, most often Psychotria viridis.
Recorded as history and attributed where possible. Long use establishes that a plant was widely used, not that it worked, and not that it was safe.
Worth knowing
The pharmacological interest of ayahuasca is that it is a two-plant solution to a chemical problem, and that the traditions found it without chemistry.
DMT taken orally is destroyed by monoamine oxidase in the gut and does nothing. The beta-carbolines in Banisteriopsis caapi inhibit that enzyme, which allows the DMT from a second plant to reach the brain. Neither plant alone produces the effect.
Out of tens of thousands of Amazonian species, two specific plants from unrelated families, combined and prepared in a particular way. How that was arrived at is a genuinely open question, and the traditions' own answer — that the plants taught them — is not one this site can assess and not one it will dismiss.
The MAO inhibition is also why ayahuasca tourism kills people. A visitor on an ordinary antidepressant is taking a drug combination with a known and serious fatality risk.
Nomenclature verified against GBIF backbone taxonomy.