Ayahuasca is a psychoactive brew originating in the Amazon basin, made by combining two plants whose chemistry would be unremarkable on its own but becomes powerfully psychedelic when paired together. The drink has been used by Indigenous peoples of South America for centuries in spiritual and healing contexts, and over the past two decades it has drawn serious attention from psychiatric researchers studying depression, addiction, and the neuroscience of consciousness. The story of ayahuasca is really about an unlikely pharmacological partnership between two plants, the surprisingly specific ways the brew reshapes brain activity, and a growing body of clinical evidence that is cautiously optimistic but far from settled.
Why Two Plants Instead of One
The traditional preparation combines the bark and stems of the vine Banisteriopsis caapi with the leaves of the shrub Psychotria viridis. Neither plant would produce much of a psychedelic effect if consumed alone. Psychotria viridis contains DMT (N,N-dimethyltryptamine), a compound that is a potent psychedelic in its own right but gets broken down almost immediately by an enzyme in your gut called monoamine oxidase, or MAO. Swallowing DMT by itself would accomplish very little because your digestive system neutralizes it before it reaches the bloodstream.
This is where the vine comes in. Banisteriopsis caapi contains a family of compounds called beta-carboline alkaloids, primarily harmine, harmaline, and tetrahydroharmine (THH). These compounds temporarily and reversibly block the MAO enzyme.1PubMed. Metabolism and disposition of N,N-dimethyltryptamine and harmala alkaloids after oral administration of ayahuasca With MAO suppressed, DMT from the leaves survives digestion, gets absorbed into the bloodstream, crosses into the brain, and produces a psychedelic experience that typically lasts four to six hours.2Journal of Agricultural Studies. A Systematic Literature Review of the Potential Therapeutic Effects of Ayahuasca Tea Prepared From the Use of Banisteriopsis Caapi and Psychotria Viridis The result is also a surge in serotonin levels, which likely contributes to both the altered state of consciousness and some of the brew’s antidepressant effects.
The brew itself is more chemically complex than just “DMT plus an MAO inhibitor.” Traditional preparations contain polyphenols, organic acids, carbohydrates, and numerous other plant-derived compounds that researchers are still cataloguing.3International Journal For Multidisciplinary Research. A Matrix-Reduced Whole-Plant Approach to Ayahuasca Preparation: Co-Extraction of Banisteriopsis caapi and Psychotria viridis Whether these additional compounds contribute meaningfully to the psychological or therapeutic effects remains an open question, but it is one reason researchers hesitate to equate ayahuasca with synthetic DMT-plus-inhibitor combinations.
What Ayahuasca Does to Brain Activity
One of the more consistent neuroimaging findings involves the default mode network (DMN), a set of brain regions that is most active when you are not focused on the outside world. Think daydreaming, ruminating, self-referential thought. In people with depression, the DMN tends to be overactive, locked into repetitive negative thought loops. Ayahuasca appears to dial it down. A study using functional MRI found that the brew caused significant decreases in activity across most parts of the DMN, including its two main hubs: the posterior cingulate cortex and the medial prefrontal cortex.4PLoS ONE. The Psychedelic State Induced by Ayahuasca Modulates the Activity and Connectivity of the Default Mode Network Connectivity within the posterior cingulate cortex also dropped during the ayahuasca state.
A systematic review covering multiple psychedelics confirmed this pattern and added further detail: while internal DMN connectivity decreased, connections between the DMN and other networks, such as the salience network and the visual network, increased.5PubMed Central. Default Mode Network Modulation by Psychedelics: A Systematic Review In plain terms, the brain’s usual boundaries between functional networks loosened. This may be why people under the influence of ayahuasca describe a dissolving of their ordinary sense of self: the neural architecture that normally maintains a stable, separate “you” becomes temporarily more fluid.
There is also interest in whether ayahuasca promotes neuroplasticity, the brain’s ability to form new connections. One study found that ayahuasca increased levels of BDNF, a protein linked to the growth and survival of neurons, in both healthy people and those with depression. However, another study found no change, so the evidence here is mixed.6Neuropsychopharmacology. Towards an understanding of psychedelic-induced neuroplasticity Whether the brew genuinely rewires the brain or simply opens a temporary window of psychological flexibility is still being worked out.
The Depression Research
The most rigorous clinical evidence for ayahuasca as a psychiatric treatment comes from a randomized, placebo-controlled trial in Brazil involving patients with treatment-resistant depression. A single dose of ayahuasca produced antidepressant effects that were visible as early as the next day, with depression scores significantly lower than placebo at one day, two days, and seven days after the session. The effect actually grew over time: the difference between groups was largest at the seven-day mark, with a large effect size. By day seven, about two-thirds of the ayahuasca group met criteria for treatment response, compared to about a quarter in the placebo group.7PubMed Central. Rapid antidepressant effects of the psychedelic ayahuasca in treatment-resistant depression: a randomized placebo-controlled trial
These are striking numbers, especially for people whose depression had not responded to conventional medication. But the study was small (29 participants), and the psychedelic experience itself makes true blinding difficult: people generally know whether they received a psychoactive substance or not. A separate observational study found that a majority of 20 individuals with major depression experienced remission lasting a year after participating in a ritual involving botanical ayahuasca analogues.8PubMed Central. Neurobiological research on N,N-dimethyltryptamine (DMT) and its potentiation by monoamine oxidase (MAO) inhibition: from ayahuasca to synthetic combinations of DMT and MAO inhibitors That kind of durability from a single intervention would be remarkable if confirmed in larger trials, but observational studies without control groups can only take you so far.
The honest assessment is that the signal is strong enough to justify larger and more carefully designed trials, but not yet strong enough to declare ayahuasca an established depression treatment. The field is roughly where ketamine research was a decade ago: exciting preliminary data, mechanistic plausibility, and a need for the kind of large-scale studies that take years and millions of dollars to complete.
Addiction and Substance Use
A different line of research has explored whether ayahuasca can help with substance use disorders. A systematic review of both animal and human studies found mostly encouraging results: all animal studies showed improvement in behavioral or biochemical measures related to drug-induced problems, and four of five human studies reported significant reductions in dependence symptoms or substance use.9PubMed. Effects of Ayahuasca and its Alkaloids on Drug Dependence: A Systematic Literature Review of Quantitative Studies in Animals and Humans
A preliminary observational study from Canada reported that participants in ayahuasca-assisted retreats showed statistically significant improvements in hopefulness, empowerment, mindfulness, and quality of life. Self-reported use of alcohol, tobacco, and cocaine declined, with reductions in problematic cocaine use reaching statistical significance. Cannabis and opiate use, however, did not change.10PubMed. Ayahuasca-assisted therapy for addiction: results from a preliminary observational study in Canada The fact that the brew seemed to help with some substances but not others is interesting and underexplored. It could reflect differences in the underlying neurobiology of each addiction, or it could simply be an artifact of a small sample.
What makes this research particularly difficult to interpret is the ceremonial context. Ayahuasca-assisted addiction retreats typically involve group support, preparation sessions, integration discussions, dietary restrictions, and a strong sense of ritual. Disentangling the pharmacological effects of the brew from the therapeutic scaffolding around it is one of the central challenges for researchers in this space.
Mindfulness Without the Meditation
One of the more unexpected findings in ayahuasca research is that a single session appears to produce psychological shifts that normally require weeks or months of mindfulness meditation practice. A study measuring several facets of mindfulness found that ayahuasca intake led to significant increases in non-judgmental awareness and decentering ability, the capacity to observe your own thoughts and feelings without getting swept up in them. The researchers noted that these scores fell within the range observed after extensive mindfulness training.11PubMed. Exploring the therapeutic potential of Ayahuasca: acute intake increases mindfulness-related capacities
A follow-up comparison study pitted four weekly ayahuasca sessions against a standard eight-week mindfulness training program. The ayahuasca group showed a significant improvement in the “non-judging” facet of mindfulness, while the other facets (observing, describing, acting with awareness, and non-reacting) showed trends in the right direction but did not reach statistical significance.12PubMed Central. Four Weekly Ayahuasca Sessions Lead to Increases in “Acceptance” Capacities: A Comparison Study With a Standard 8-Week Mindfulness Training Program The results suggest ayahuasca does not replicate the full suite of psychological changes that come from sustained meditation practice, but it may fast-track certain aspects of it, particularly the ability to step back from harsh self-judgment.
This connects to the DMN findings described earlier. The ruminative, self-critical loops that characterize depression are supported by the same default mode circuitry that ayahuasca appears to quiet. If the brew temporarily disrupts those loops while simultaneously boosting a capacity for non-judgmental self-observation, it is not hard to see how that combination could produce lasting psychological benefit for some people.
Safety, Side Effects, and Dangerous Combinations
Ayahuasca is not physically gentle. A large global survey found that about 70% of users reported acute physical side effects, with vomiting being the most common. In many ceremonial traditions, purging is considered a feature rather than a bug, an integral part of the healing process. About 2.3% of survey respondents reported needing medical attention afterward.13PubMed Central. Adverse effects of ayahuasca: Results from the Global Ayahuasca Survey For most healthy people, the physical discomfort passes within hours and does not require treatment. Psychological distress during the experience, sometimes called a “difficult trip,” is also common and can range from mild anxiety to genuinely frightening experiences.
The most serious safety concern involves drug interactions. Because ayahuasca contains potent, reversible MAO inhibitors, combining it with medications that increase serotonin levels is dangerous. The interaction between the harmala alkaloids in the brew and SSRIs (selective serotonin reuptake inhibitors, the most commonly prescribed class of antidepressants) can trigger serotonin syndrome, a potentially life-threatening condition involving dangerously high serotonin activity.14PubMed. Ayahuasca preparations and serotonin reuptake inhibitors: a potential combination for severe adverse interactions This risk extends to other serotonergic medications, including certain migraine drugs and some pain medications. Anyone on psychiatric medication who is considering ayahuasca needs to understand that this is not an abstract caution: the interaction can cause seizures, dangerously high body temperature, and death.
Foods and supplements that affect serotonin or tyramine levels can also interact with MAO inhibitors. Ceremonial ayahuasca traditions often include dietary restrictions in the days before a session (sometimes called “dieta”), and while these are typically framed in spiritual terms, they overlap meaningfully with the medical advice around MAO inhibitor safety.
Long-Term Cognitive and Mental Health Effects
A natural question for anyone interested in ayahuasca is whether repeated use over months or years causes any lasting cognitive damage. A cross-sectional study comparing long-term ritual users found no evidence of cognitive decline. In fact, experienced users scored higher than less experienced users on tests of working verbal and visuospatial memory, though cross-sectional designs cannot prove that the ayahuasca caused the difference.15PubMed. Long-term ayahuasca use is associated with preserved global cognitive function and improved memory: a cross-sectional study with ritual users It is plausible that people with better memory are simply more likely to continue using ayahuasca over time, or that the lifestyle and social engagement surrounding regular ceremonial participation contribute to cognitive maintenance.
On the mental health side, a study of ceremonial ayahuasca users in Estonia found that the ayahuasca-using group had lower indicators of depression and anxiety compared to non-users. There was no sign of mental health deterioration among the users, who described their practice as a form of spiritual engagement with mostly favorable outcomes for their health and wellbeing.16PubMed. Ayahuasca Users in Estonia: Ceremonial Practices, Subjective Long-Term Effects, Mental Health, and Quality of Life Again, these are observational comparisons, not randomized trials: the kind of person who seeks out and continues ayahuasca ceremonies may differ from the general population in ways that affect mental health independent of the brew itself.
Anti-Inflammatory Effects
Beyond the brain, there is growing interest in ayahuasca’s effects on the immune system. Research has linked the pharmacological activity of the brew to anti-inflammatory mechanisms, particularly through DMT and a related compound (5-MeO-DMT) acting on sigma-1 receptors. These receptors appear to play a role in regulating inflammation and immune balance throughout the body.17PubMed. Anti-inflammatory activity of ayahuasca: therapeutical implications in neurological and psychiatric diseases This is relevant because chronic low-grade inflammation has been increasingly implicated in psychiatric conditions, including depression and neurodegenerative diseases. If ayahuasca reduces inflammation through a mechanism separate from its psychedelic effects, that would add another dimension to its therapeutic profile. This line of research is still young, mostly based on preclinical work, and it would be premature to claim anti-inflammatory benefit in humans based on the data so far.
DMT in Your Own Brain
One of the more fascinating tangential discoveries in this field is that DMT is not just a plant compound. It appears to be produced naturally in the mammalian brain. Research in rats demonstrated that the enzyme responsible for synthesizing DMT is present in brain tissue and that DMT is produced at concentrations comparable to other well-known neurotransmitters like serotonin and dopamine. Gene expression data from human tissue suggests that the same biosynthetic machinery exists in the human cerebral cortex and pineal gland.18Scientific Reports. Biosynthesis and Extracellular Concentrations of N,N-dimethyltryptamine (DMT) in Mammalian Brain
Nobody yet knows what endogenous DMT does under normal conditions. Speculation ranges from a role in dreaming to involvement in the neurochemistry of near-death experiences, but these ideas are currently more interesting than they are supported by hard evidence. What the finding does establish is that DMT is not an exotic foreign molecule your brain has no idea how to handle. It is something your brain already makes and has receptors for, which may help explain why the psychedelic experience, while intense, does not appear to cause structural brain damage even after repeated exposure.
The Subjective Experience and Why It Varies
People describe ayahuasca sessions in terms that range from profoundly mystical to emotionally harrowing. A study comparing ayahuasca ceremonies to rituals using jurema (a different psychoactive plant preparation) found that ayahuasca sessions scored significantly higher on measures of temporal distortion, ineffability (the feeling that the experience cannot be put into words), and religious quality. Ego dissolution, the sense that the boundary between self and world has dissolved, correlated with different qualities depending on the substance used: in ayahuasca sessions, it was linked to feelings of temporal and unifying quality, while in jurema sessions it correlated more with religious and inner subjective qualities.19Taylor & Francis Online (The International Journal for the Psychology of Religion). Mystical and Ego-Dissolution Experiences in Ayahuasca and Jurema Holistic Rituals: An Exploratory Study
This underscores something researchers are still grappling with: the subjective character of a psychedelic experience is not determined solely by the drug’s pharmacology. Set (your mindset going in) and setting (the physical and social environment) powerfully shape what happens. A clinical session in a hospital room and a ceremonial session in an Amazonian maloca produce different subjective experiences even when the chemistry in the cup is similar. Whether those differences matter for therapeutic outcomes is an active area of investigation.
Non-Hallucinogenic Offspring
For pharmaceutical companies and some researchers, the ideal outcome would be to capture whatever is therapeutically useful about ayahuasca’s effects while ditching the six-hour psychedelic experience that makes it impractical as a standard treatment. This has led to the development of so-called psychoplastogens: compounds designed to promote neuroplasticity without causing hallucinations. One such compound, zalsupindole, has shown in animal studies that it promotes the growth of neurites and dendritic spines through mechanisms related to the serotonin 2A receptor, similar to classic psychedelics. It penetrates the brain rapidly in rats, shows no evidence of hallucinogenic-like behavior (no head-twitch response, the standard animal proxy for psychedelic activity), and does not activate the serotonin 2B receptor, a target associated with cardiac side effects.20PubMed. Zalsupindole: A Non-Hallucinogenic Psychoplastogen Advancing Psychedelic-Inspired Therapeutics
Whether these compounds will deliver therapeutic benefits comparable to the full psychedelic experience remains to be seen. Some researchers argue that the subjective experience, the emotional processing, the ego dissolution, the encounter with personally meaningful imagery, is itself a critical ingredient in therapeutic change, not just a side effect to be engineered away. Others point out that if neuroplasticity can be promoted without requiring a supervised six-hour trip, the potential patient population grows enormously. Both perspectives have merit, and the answer will come from head-to-head clinical trials that are still years away.
Legal Patchwork
DMT is classified as a Schedule I controlled substance in the United States and is similarly restricted under the 1971 United Nations Convention on Psychotropic Substances in most countries. Ayahuasca, however, occupies a legal gray area because the brew itself is not explicitly scheduled in many jurisdictions. Brazil explicitly permits the religious use of ayahuasca, a framework that developed through decades of negotiation between the government and syncretic religions like Santo Daime and the União do Vegetal. In the United States, the UDV (União do Vegetal) won a Supreme Court case in 2006 affirming its right to use ayahuasca as a sacrament under the Religious Freedom Restoration Act. Several other countries, including the Netherlands and Peru, have varying degrees of tolerance or explicit permission for ceremonial use.
The practical result is a confusing landscape. Ayahuasca retreat centers operate openly in countries like Costa Rica and Peru while participants from the United States or Europe may face legal risk transporting the brew or its ingredients across borders. Underground ayahuasca ceremonies operate in most Western countries, usually under ambiguous legal cover. Research has generally been permitted under controlled conditions with regulatory approval, but the regulatory pathway for a potential ayahuasca-based psychiatric medicine is substantially more complex than for a single-molecule drug, because the brew is a complex botanical preparation with batch-to-batch variation in alkaloid content.
Indigenous Roots and the Appropriation Question
Archaeological and ethnographic evidence suggests that Amazonian peoples have used Banisteriopsis species for centuries, possibly millennia. Ethnographic surveys of Indigenous groups in Ecuador document elaborate belief systems and healing practices organized around ayahuasca and related plant preparations, with the brew serving roles in divination, communication with spirits, diagnosis of illness, and social decision-making.21Journal of Ethnopharmacology. Hallucinogenic plant use and related indigenous belief systems in the ecuadorian amazon The knowledge of which plants to combine and how to prepare them represents a sophisticated pharmacological achievement that predates Western pharmacology by centuries.
As ayahuasca has gone global, questions of cultural appropriation and benefit-sharing have become increasingly pointed. The growing retreat industry generates significant revenue, very little of which flows back to the Indigenous communities that developed and preserved the knowledge. The Nagoya Protocol, an international agreement on access to genetic resources and traditional knowledge, theoretically provides a framework for equitable sharing, but enforcement in the context of plant-based traditional medicines has been minimal. Some Indigenous organizations have pushed back publicly, arguing that the commercialization of ayahuasca strips away the cultural and spiritual context that gives the practice its meaning and safety. Others have participated in cross-cultural sharing more willingly, viewing it as a way to preserve traditions that are under threat from deforestation and cultural assimilation. The tension is real and does not have an easy resolution.