Plant Medicine & PsychedelicsAyahuasca · Psilocybin · Iboga · Mescaline · 5-MeO-DMT · Kambo
The science is real and among the most promising work in modern psychiatry. The deaths are also real. This page will tell you which medications can hurt you, who has actually died and how, and why the integration nobody sells you is the part that mattered.
If you are taking any antidepressant — SSRI, SNRI, MAOI, tricyclic — or any other psychiatric or serotonergic medication, talk to a doctor or pharmacist before you go near ayahuasca or any MAOI-containing brew.
Do not stop a psychiatric medication in order to attend a retreat. Retreats routinely ask people to. Stopping an antidepressant incorrectly is dangerous on its own — discontinuation effects, and the return of the depression that the medication was holding — and the person telling you to stop it is not qualified to manage what happens next.
Nothing on this page can clear you for anything. There is no combination of substance and medication that this page will tell you is safe. That decision needs somebody who can see your notes.
And if you are in mental health crisis right now: this is not the moment and a retreat is not the place. Please talk to a doctor or a crisis line. The clinical trials exist precisely because they have the screening and the safety net that a retreat does not.
How to read this page
Part I takes the traditions and the practice seriously and teaches them properly — what these substances are, how they are actually used, what a well-run container looks like, and what integration means in concrete terms. Part II is the hard information: the pharmacology, the documented deaths, the psychiatric risk, the abuse problem, and the honest current state of the clinical science.
The medicine moves the state. It does not, by itself, change your life. The ceremony is the easy part. The integration is the work, and nobody sells tickets to it.
The traditions are real — and older, and younger, than you think
Both halves of that sentence matter, and the marketing keeps only the first.
Genuinely ancient and genuinely living
- Transmitted Peyote — used by Indigenous peoples of Mexico and North America for millennia, and central to the Native American Church, whose sacramental use is protected under US federal law for NAC members. ⚠ This is a closed practice, and peyote is additionally slow-growing and now under real pressure from over-harvest.
- Transmitted Iboga and the Bwiti — a living initiatory religion in Gabon, with its own structure, its own initiates, and its own reasons.
- Attested Mushrooms in Mesoamerica — teonanácatl, and the Mazatec velada. §01a below is about what happened when that became public.
⚠ Ayahuasca is more complicated than the marketing implies
Contested There is serious scholarship — Peter Gow and Bernd Brabec de Mori among others — arguing that ayahuasca as a brew and ceremony may be considerably more recent than “ancient Amazonian wisdom” suggests: possibly originating around the Napo river basin and spreading through Jesuit mission settlements and the rubber camps of the colonial and rubber-boom periods, perhaps within the last five hundred years.
The evidence offered: widespread Catholic features embedded in ceremonies among otherwise unrelated peoples, and the fact that a number of Amazonian groups report first encountering ayahuasca within living memory. The Iskonawa, in contact with ayahuasca-using neighbours for generations, had reportedly never heard of it as late as 1959.
⚠ Hold this carefully. It is contested scholarship, not settled fact, and Indigenous nations have their own oral histories which say otherwise and which are not ours to overrule. What can be said plainly is narrower and still useful: the plants are old; the ceremony you would attend as a tourist is substantially a modern construction.
Attested The large ceremonial churches are twentieth-century and Brazilian: Santo Daime, founded around 1930 by Raimundo Irineu Serra; the Barquinha; and the União do Vegetal, founded by José Gabriel da Costa. These are syncretic religions blending shamanic, spiritualist and Christian elements, and they are real religions with real congregations — not the same thing as a retreat.
And the parts that are very new indeed
- Contemporary 5-MeO-DMT ceremony — “the God molecule,” “Bufo” — is largely a late-twentieth and twenty-first century Western practice. The toad-derived version raises genuine conservation and animal-welfare problems.
- Contemporary “Plant medicine” as a Western wellness category — the retreat, the tourism, the influencer, the booking site — is almost entirely twenty-first century.
What happened to María Sabina
Attested In 1955, R. Gordon Wasson — a vice-president of J.P. Morgan and an amateur ethnomycologist — travelled to Huautla de Jiménez in Oaxaca with a photographer and persuaded María Sabina, a Mazatec curandera, to let them take part in a velada. In May 1957 he published a fifteen-page account in Life magazine.
He had given her a pseudonym and obscured the location. Neither held.
What followed is documented and it is grim. Huautla filled with seekers. The velada was commodified. Sabina was blamed by her own community for revealing what should not have been revealed: her practice was raided by Mexican authorities, her home was burned down, her son was murdered, and she died destitute in 1985. She said afterwards that the mushrooms had lost their power. Wasson, by his own account, deplored what he had set in motion.
This is the cautionary tale at the root of the entire Western psychedelic movement, and almost nobody entering it is told about it. When someone offers you access to a sacred practice that is not theirs to sell, this is the shape of what that access has cost before.
The substances, honestly described
What each one actually is, how it is used, and what the experience is like. Risk is covered properly in Part II — this section is the description.
What it is: a brew, usually of the Banisteriopsis caapi vine with a DMT-containing leaf such as Psychotria viridis. The vine supplies harmine, harmaline and tetrahydroharmine; the leaf supplies DMT.
Why the combination: DMT taken by mouth is destroyed in the gut by monoamine oxidase before it reaches the brain. The vine's alkaloids inhibit that enzyme, which is what makes the brew orally active. This is not incidental — it is the entire pharmacological point, and it is also the source of the interaction danger in §05.
The experience: four to six hours, usually at night, usually in a group, with singing. Vomiting and diarrhoea are common and are traditionally understood as part of the process rather than a side effect.
What it is: psilocybin, converted in the body to psilocin, acting largely at the 5-HT2A receptor.
The experience: four to six hours. The best-evidenced substance in this whole field, and the one furthest along in clinical development.
Setting: ranges from Mazatec velada to Dutch truffle retreat to Phase 3 trial — three entirely different things wearing one word.
What it is: an alkaloid from the root bark of Tabernanthe iboga, used in Bwiti initiation and, in the West, as an anti-addiction treatment.
The experience: extraordinarily long — twenty-four to thirty-six hours or more, with prolonged ataxia.
⚠ This is the most cardiotoxic substance on this page by a wide margin. See §06 before anything else.
What it is: a phenethylamine from several cacti. Peyote is slow-growing, threatened, and central to a closed tradition; San Pedro (huachuma) grows fast and is used in Andean practice.
The experience: long — ten to fourteen hours — with a heavy body load. Lower acute toxicity than most here, but real cardiac and interaction risk.
What it is: a tryptamine, either synthetic or milked from the Incilius alvarius toad. Smoked or insufflated.
The experience: extremely fast and extremely powerful — onset in seconds, peak in minutes, largely over in twenty to thirty. Frequently total loss of self and of any capacity to cooperate with the people in the room.
⚠ The speed is the danger. There is no window in which to reconsider, and adverse events cluster around second doses and mishandled medical events.
What it is: not a psychedelic at all. The secretion of the giant monkey frog, Phyllomedusa bicolor, applied to deliberately made superficial burns. Sold in the same spaces, so it belongs on the same page.
The experience: violent vomiting, flushing, swelling, racing heart, over roughly twenty to forty minutes.
⚠ It has a specific and well-documented mechanism of death. See §06.
What a well-run container actually looks like
Taught in full, because the difference between a good container and a bad one is most of the difference between benefit and harm — and because knowing what good looks like is how you recognise what bad looks like.
- Screening that can say no. Medical history, medication list, cardiac history, personal and family psychiatric history. A screening process that has never turned anyone away is not a screening process, it is a form.
- Preparation, over weeks rather than hours. In clinical trials this is a substantial intervention in its own right: hours spent building trust with the people who will sit with you, learning what may happen, and setting intention. The retreat that flies you in on Friday and doses you on Saturday has skipped it.
- Set and setting, properly understood. Not just the room and the cushions. Set is what you bring — expectation, belief, fear, preparation, trust. Setting is everything around you, including who is in the room and whether you are safe with them. A frightened, unprepared person among strangers is set up badly regardless of the substance's quality.
- Sober, competent, sufficient sitters. People who are not dosed, who stay awake, who know what they are watching for, and enough of them. Someone in difficulty needs a person, not a shared one.
- An actual medical plan. Where is the nearest hospital, how long does the drive take, who calls, who has the car keys, what is the phone signal like. Ask these questions out loud and watch the answer arrive or fail to.
- Consent that survives the dose. Agreed beforehand: who may touch you and where, what happens if you want to stop, who is allowed in the room. You cannot give consent while dosed. That is the whole of §08.
- Closing and aftercare. Somewhere to sleep, food, quiet, and someone reachable the next day and the week after.
Every item on that list is boring. The boring items are the ones that were doing the work.
Integration, defined properly
“Do your integration” is useless advice without a definition, and the vagueness is convenient for people selling ceremonies. So here is a definition.
Integration is the process of translating an experience into durable change.
It generally includes making meaning of what happened; discussing it with a competent person; changing actual behaviour; repairing relationships; working with trauma that surfaced; letting the nervous system re-stabilise; and returning fully to ordinary life.
Each of these feels like integration and is commonly mistaken for it. Tap one to see what it is instead, and what the integrated version of the same thing would look like.
- Remembering the experience is not integration.
- Feeling changed is not integration.
- Living differently six months later is integration.
Integration is slow — months, not a weekend. It is active: you do it, the medicine does not do it for you. It works largely at the level of body and belief, the domains that only shift under sustained engagement. And it is impossible inside the ceremony, because the ceremony is a passive, state-level event and integration is active, trait-level work.
⚠ The interaction, exactly
This is the section that has to be precise, so it is going to be more careful than the warnings you have probably read — in both directions.
The mechanism
Studied Ayahuasca's β-carbolines — harmine, harmaline and tetrahydroharmine — are inhibitors of monoamine oxidase A. That is what stops your gut destroying the DMT, and it is why the brew works at all.
Inhibit MAO-A and you reduce the body's capacity to break down serotonin. Add an SSRI or SNRI, which blocks serotonin reuptake, and you have two mechanisms pushing serotonin in the same direction at once. The theoretical result is serotonin syndrome — agitation, tremor, rigidity, hyperthermia, in severe cases death. Callaway and Grob described the risk in print in 1998 and the concern has been in the literature ever since.
⚠ Now the honest part, in both directions
The harmala alkaloids are reversible inhibitors of MAO-A, which is pharmacologically a meaningfully gentler thing than the classic irreversible MAOI antidepressants. And a 2024 systematic review of ayahuasca and DMT adverse events found that serotonin syndrome in combination with psychiatric drugs appears in extremely rare case reports, with no confirmed cases identified. The catastrophe is not happening at the rate the warnings imply.
Rare is not never, and serotonin syndrome can kill. Every clinical trial in this field screens for and excludes serotonergic medication — the people with the most at stake in a positive result treat this as a hard exclusion. Brew strength is unstandardised, some brews contain additional admixture plants, and you will be hours from a hospital with people who cannot recognise the syndrome. The dose you get is not the dose anyone measured.
⚠ And the danger that is actually well documented
It is not the one people warn about. It is the tapering. Retreats routinely instruct people to come off antidepressants in order to attend. That instruction is where the reliable harm lives:
- Discontinuation is a real clinical event, not an inconvenience, and doing it on a retreat's schedule rather than a prescriber's is how it goes wrong.
- The depression comes back. The medication was doing something. The people drawn to ayahuasca for depression are, definitionally, people with depression.
- It is being managed by someone with no medical training, who has taken your money, and who is not going to be reachable in three weeks.
Nobody at a retreat is qualified to take you off a psychiatric medication. If that instruction arrives in an email, the email is the red flag — not the brew.
Categories, all visible. Tap any one to see the specific concern. There is no combination this page will tell you is fine, and the absence of your medication from this list means nothing.
⚠ Deaths and serious harm, by substance
Documented, sourced, and rare — but real. Presented plainly because the retreat that took your money will not present it at all.
⚠ Psychiatric risk — the under-warned half
- ⚠ A personal or family history of psychosis, schizophrenia or bipolar disorder is a serious contraindication. Psychedelics can precipitate psychosis or mania, and it does not always resolve when the drug does. A published case describes a switch to mania after ayahuasca in a man with a family history of bipolar disorder. Family history counts, and most retreats never ask.
- Hallucinogen Persisting Perception Disorder — persistent visual disturbance after use. Real, uncommon, and occasionally lasting.
- Prolonged destabilisation. Some people are not “still integrating” three months later — they are unwell, frightened, derealised or in crisis. This happens, it is not rare enough to ignore, and the retreat that took your money is not answering emails.
- Trauma with no off-switch. These substances can surface traumatic material with overwhelming force and no way to stop or slow it. Without skilled support that is not processing; it is retraumatisation with better lighting.
⚠ The setting, the “shaman,” and sexual abuse
There is no licensing body. “Shaman,” “curandero,” “facilitator” are unregulated titles that anybody may claim. The feathers, the white clothing and the icaros are a costume, and a costume is not a credential.
Financial exploitation, coercion and full cult dynamics also cluster around charismatic retreat leaders — the spiritual-abuse page describes the mechanism in detail. And basic physical safety failures are real: people have wandered off, fallen, and drowned for want of somebody watching.
The science is real — current as of July 2026
⚠ Do not let Part II's risk sections leave you thinking the science is fringe. It is not. This is among the most serious areas of psychiatric research now underway, and the page would be dishonest if it buried that.
- Studied Psilocybin for depression, including treatment-resistant depression, has produced striking controlled-trial results, with positive Phase 3 data reported in 2025. Compass Pathways is targeting a New Drug Application submission for its psilocybin formulation in late 2026. This is the furthest-advanced programme in the field.
- Studied Psilocybin for end-of-life anxiety in terminal illness — some of the most moving and robust findings anywhere in psychiatry.
- Contested MDMA for PTSD is the honest complication, and it deserves the full story. Lykos Therapeutics submitted an application on the strength of two Phase 3 trials. In June 2024 an FDA advisory committee voted 10–1 against recommending approval, and in August 2024 the FDA declined to approve it, requiring an additional Phase 3 trial. Concerns included safety reporting, durability, allegations of misconduct during trials, and functional unblinding. Lykos cut roughly three-quarters of its staff within weeks. The FDA published the complete response letter in September 2025; MAPS accused the agency of moving the goalposts. The promise is real and so are the problems.
- Studied Ibogaine for opioid addiction — a genuine efficacy signal, permanently shadowed by the cardiac risk in §06. The promise and the danger are the same molecule.
- The methodological problem worth understanding. Functional unblinding means participants can tell whether they got the drug, because the effects are unmistakable — which biases everything downstream through expectation. In July 2026 the FDA finalised guidance for psychedelic trials specifically addressing it, requiring active placebos, blinding questionnaires, expectancy controls and complementary trial designs. This is the field being made to do the hard version, and it is a good sign rather than a bad one.
In the trials, the drug is a small part of a large, careful structure. The retreat sells you the molecule and skips the structure. The structure is what produced the results.
Three interventions, sold as one
Preparation, ceremony and integration are three different interventions. Most commercial retreats sell only the middle one — and it is the one that does least on its own.
| Clinical trial | Typical retreat |
|---|---|
| Screening that excludes people, on medical and psychiatric grounds | A form, and sometimes a phone call |
| Hours of preparation with the people who will sit with you | Arrive Friday, dose Saturday |
| Medical supervision, monitoring, a plan | Variable; frequently hours from a hospital |
| The dosing session | The dosing session |
| Structured integration therapy with trained clinicians | A group share at breakfast, and a booking link for next time |
| Follow-up over months | An email newsletter |
Both columns contain the ceremony. Only one contains everything else. When you read that the trials produced large effects, the effects were produced by the whole column.
⚠ Why the state-and-trait distinction matters most here
Practitioner This section applies the school's own framework, and is marked as such.
The medicine reaches all four domains at once — nervous system, body, belief, orientation — at a resolution ordinary practice rarely achieves. That is real, and it is why this can be genuinely valuable.
But it reaches them as a state, not a trait. The window is hours. Then it closes. And the nervous system is frequently not settled during and after but profoundly perturbed — which is why the coherence grid marks this as capable of dysregulating rather than regulating. Intensity is not stability. The intensity is not the healing; it is the opening.
The experience is not the healing. The integration is the healing. And you can be sold the first while being left entirely alone for the second.
This is why people attend ceremony after ceremony, feel profound every time, and do not change. Each ceremony is another state. Without integration no state becomes a trait. They are paying, repeatedly, for the opening — and skipping the work.
The steelman
- The clinical science is real and important. For treatment-resistant depression, PTSD and end-of-life distress this may prove among the most significant developments in psychiatry in fifty years. Dismissing it is as foolish as overselling it.
- The traditions are genuine — living, initiatory, coherent on their own terms, and owed respect as religions rather than treated as inputs to a Western wellness product.
- Profound and genuinely valuable experiences do happen. People have encounters that reorient their lives — particularly, and predictably, when the integration work actually gets done.
- The window is real. The medicine can show you all four domains at a resolution you might never otherwise reach. That map is worth having, if you then do something with it.
- Some retreats and facilitators are excellent, careful and ethical. They exist. They screen people out, they ask about your medications, they employ sober sitters, and they will tell you not to come. They are also not the ones with the biggest advertising budgets.
⚠ Risk — consolidated
Legal reality — and this section dates fast
Stated as of July 2026. Check current law where you are before relying on any of it.
- Most of these remain controlled substances in most countries. Possession can mean prosecution, prison and a permanent record.
- Retreat tourism operates in a legal grey zone — legal or tolerated in parts of South America, and for psilocybin truffles in the Netherlands; illegal in most places.
- Some religious use is protected — Native American Church peyote use in the US, and certain ayahuasca-church exemptions in some jurisdictions. ⚠ These protections are narrow and do not extend to tourists.
- MDMA is not approved in the United States and remains Schedule I. Australia is currently the only country where MDMA can be legally prescribed, for PTSD, under the Therapeutic Goods Administration's Authorised Prescriber scheme since July 2023.
- US state frameworks are diverging from federal law. Colorado's Natural Medicine Health Act, passed in 2022, decriminalised personal possession of psilocybin, DMT, ibogaine and mescaline for adults over 21; Oregon operates a supervised psilocybin services framework. Neither makes these substances federally legal.
- Ketamine is the outlier worth knowing about: legally available, FDA-approved in one form for treatment-resistant depression, and therefore the only route in this territory that does not require breaking a law.
What a new seeker should actually ask
- ⚠ What am I currently taking — every medication, especially antidepressants? Ask this of a doctor or pharmacist, not a facilitator. This question has saved lives.
- ⚠ Do I, or does anyone in my family, have psychosis, schizophrenia or bipolar disorder? If yes, talk to a psychiatrist before you talk to anybody else.
- ⚠ Has anyone screened my heart? Especially for ibogaine, where this is the difference between a treatment and a death.
- ⚠ Is there a real plan for a medical emergency, and how far is the nearest hospital? Ask for the drive time in minutes.
- Who is running this, what can I verify independently, and who have they harmed?
- What is the integration support — included, or am I alone the day after? If there is no integration plan, you are buying a state and nothing else.
- Am I hoping the medicine will do the work for me? It won't. It can only show you the work.
- Am I chasing ceremony after ceremony? Then the ceremonies are not the answer; the integration between them is the part being skipped.
- Is this legal where I am, and am I prepared for the consequences if it isn't?
Provenance
The ayahuasca–SSRI interaction Studied
Callaway & Grob (1998), Ayahuasca preparations and serotonin reuptake inhibitors: a potential combination for severe adverse interactions. Mechanism: harmine, harmaline and tetrahydroharmine as reversible MAO-A inhibitors. Counter-evidence on frequency: White, Kennedy, Ruffell, Perkins & Sarris (2024), systematic thematic review of ayahuasca and DMT adverse events — extremely rare case reports, no confirmed cases identified.
Ibogaine cardiotoxicity Studied
hERG potassium channel blockade by ibogaine and noribogaine → QTc prolongation → torsades de pointes. Alper et al. (2012), 19 fatalities 1990–2008, later updated to approximately 33. Published case reports of cardiac arrest at 200 mg (2.6 mg/kg) without structural heart disease. Brunt et al. (2026), Addiction, on CYP2D6 variability. Monitored-cohort contrast: 191 patients on continuous telemetry with genotyping, no significant arrhythmias.
Kambo Studied
Phyllomedusa bicolor peptides → SIADH → hyponatremia and cerebral oedema. Leban, Kozelj & Brvar (2016), Toxicon. Campodónico et al. (2019), Revista Médica de Chile. Tran et al. (2025), Cureus — first documented case of brain death attributed to kambo toxicity.
Sexual abuse in ayahuasca settings Studied
Chacruna Institute, Ayahuasca Community Guide for the Awareness of Sexual Abuse (2018), available free in fourteen languages with a legal-resources companion. Peluso et al. (2020), Journal of Psychedelic Studies 4(1). Chacruna's 2020 Ayahuasca Survey: 2,071 respondents, 745 cases analysed, 83.1% aware, 52.1% reporting direct or indirect experience.
Clinical and regulatory status Contested
FDA Psychopharmacologic Drugs Advisory Committee vote 10–1 against, June 2024. Complete Response Letter to Lykos Therapeutics, 9 August 2024, published by the FDA 4 September 2025. FDA final guidance on psychedelic clinical trials, July 2026, addressing functional unblinding. Compass Pathways COMP360 targeting NDA submission in Q4 2026. All of this moves; date-check before relying on it.
Ayahuasca's contested antiquity Contested
Peter Gow and Bernd Brabec de Mori on a possible Napo-basin origin spreading via mission settlements and rubber camps. Evidence includes Catholic ritual features and reports of first contact within living memory among several Amazonian peoples. Contested scholarship, and Indigenous oral histories differ. Santo Daime founded around 1930 by Raimundo Irineu Serra; União do Vegetal founded by José Gabriel da Costa.
María Sabina and Wasson Attested
R. Gordon Wasson, Seeking the Magic Mushroom, Life, May 1957, describing a 1955 velada at Huautla de Jiménez. Subsequent documented consequences for Sabina: raids on her practice, her house burned, her son murdered, and her death in poverty in 1985.
The state-and-trait framing Practitioner
§11 applies the school's own coherence framework. The components are sourced on their own page; the application here is ours.
✦ For practitioners
- Never advise anyone to stop a psychiatric medication. Not a taper, not a timeline, not “most people find two weeks is enough.” It is outside your competence and it is the best-documented harm in this field.
- Screen so that people fail. Cardiac history, personal and family psychiatric history, full medication list. If you have never turned anybody away, you are not screening.
- Establish consent before the dose and honour it after. Who may touch whom, where, and what happens if someone wants to stop. A person under the medicine cannot consent, and any framework that says otherwise is doing predator's work.
- Sell integration or do not sell ceremony. If your offering ends when the sun comes up, say so plainly in your pricing, so nobody buys a state believing they bought a change.
- Know what you cannot handle, and know it in advance. Serotonin syndrome, a cardiac event, a psychotic break. If you cannot recognise them, you need somebody present who can.
✦ For those guiding others
- Ask about medications first, every time, before any other conversation. People do not volunteer it, because they have been told it disqualifies them and they want to go.
- Take the family psychiatric history seriously, even when the person waves it away. A parent's episode decades ago is relevant information and they may not know that.
- If someone comes back unwell, do not call it integration. Weeks of derealisation, fear or sleeplessness is a clinical picture and it needs a clinician. The framing that keeps people out of care is the framing that says this is just the process working.
- Never send anyone to a retreat you have not verified — and understand that a referral fee makes you part of the sales structure, whatever you intended.
- Say the boring things out loud. Drive time to hospital, who is staying sober, what the consent rules are. People remember the questions you asked in front of them long after they forget your advice.
We are not vouching for these, only pointing at them. The first is free and, if you are considering a retreat, arguably the single most useful document in this field.
- Chacruna Institute — Ayahuasca Community Guide for the Awareness of Sexual Abuse (2018). Free, in fourteen languages, with a legal companion. Read it before you book anything.
- White, Kennedy, Ruffell, Perkins & Sarris (2024) — the systematic review of ayahuasca and DMT adverse events. The careful version of the risk picture.
- Alper et al. on ibogaine fatalities, and the subsequent cardiology literature on hERG blockade.
- The FDA's Complete Response Letter to Lykos Therapeutics (published September 2025). Read what a regulator actually says when it declines something promising.
- María Sabina — her own recorded life story, and Wasson's 1957 Life article beside it. Read them together, in that order.