Part 3: Legality (or lack thereof)
(In the last post, I promised to start this one with some explanation of what goes into ayahuasca that makes it the concern of the US Drug Enforcement Agency, and why some people in the U.S. can drink it legally while others can’t. Here goes.)
Ayahuasca is most commonly defined in the literature both lay and academic as a brew made from the combination of two plants: a vine, ayahuasca (Banistseriopsis caapi); and a leaf, usually chacruna (Psychotria viridis) but sometimes chaliponga, chagroponga or yáji (Diplopterys cabrerana). Although this definition obscures the myriad historical and contemporary iterations of brews that use the ayahuasca vine as a base, the ayahuasca-chacruna dyad is the basis for the spread of ayahuasca usage in the Amazon and around the world.
The leaves that go into the ayahuasca brew contain a substance, dimethyltryptamine or DMT, that has a number of interesting characteristics. It is produced in the healthy human body and brain, and recent research (here, here, and here) suggests that it modulates the immune system and may provide other biologically protective functions as well. DMT is also produced in numerous other plant and animal species. When extracted, purified, and smoked (or injected, as it was in a series of clinical experiments that jump-started the current wave of psychedelic research), DMT produces prodigious if short-lived hallucinations. When ingested orally, however, it does nothing at all. That’s because an enzyme in the human digestive system, monoamine oxidase or MAO, breaks down the DMT before it can get into the bloodstream and through the blood-brain barrier.
On the other hand, ayahuasca the vine (and subsequently the brew) contains substances that inhibit the monoamine oxidase (we call them mono-amine oxidase inhibitors, or MAOIs), thus rendering the DMT orally active and, therefore, hallucinogenic.
The legal problem arises over the fact that DMT is a Schedule 1 substance, a classification reserved for drugs that the US government defines as having no legitimate medical use and a high potential for abuse. Possession of Schedule 1 substances is illegal. Therefore, possession of ayahuasca is, ostensibly, illegal as well.