An ayahuasca ceremony is a guided ritual, rooted in indigenous Amazonian medicine traditions, in which participants drink a psychoactive tea brewed from two plants and undergo a multi-hour experience of purging, altered consciousness, and emotional processing. Ceremonies typically last 3 to 6 hours, often beginning at midnight and ending at sunrise, and are led by a practitioner who uses chanting, music, and tobacco smoke to guide the group through the experience.
What’s in the Brew
Ayahuasca is made from two key ingredients. The vine Banisteriopsis caapi provides three alkaloids: harmine, tetrahydroharmine, and harmaline. The leaves of Psychotria viridis (or sometimes a related plant, Diplopterys cabrerana) provide DMT, a potent psychoactive compound. Neither ingredient works particularly well on its own when swallowed. DMT is rapidly broken down in the gut by an enzyme called monoamine oxidase before it ever reaches the brain. The alkaloids from the vine block that enzyme, allowing DMT to survive digestion and cross into the bloodstream. This chemical partnership is what makes ayahuasca psychoactive when taken orally, and it’s one of the enduring mysteries of indigenous plant knowledge: how Amazonian peoples identified this specific two-plant combination among tens of thousands of species in the rainforest.
Indigenous Roots of the Practice
Ayahuasca use is deeply embedded in the traditional medicine systems of the Peruvian and Colombian Amazon. Among the Shipibo people, practitioners known as onanyabo have used the brew as a cornerstone of a broader healing system called vegetalismo, which includes many plant medicines and remains the primary healthcare system in parts of the Peruvian jungle. In traditional Shipibo practice, the first ceremony in a series serves as a diagnostic session. The practitioner “scans” each participant’s body using songs called icaros, looking for what they describe as energetic blockages. Subsequent ceremonies then work to address what was found. This system treats the practitioner’s work and the plant’s effects as inseparable rather than viewing them as two distinct variables.
What Happens During a Ceremony
A ceremony moves through roughly three phases: purging, the visionary journey, and grounding.
Before drinking ayahuasca, some retreats begin with a cleansing step. This sometimes involves drinking warm tobacco water to induce vomiting, a process that must be supervised because the tobacco can be toxic in large amounts. Once the space is set, the practitioner chants over the brew to prepare it, then participants drink a small cup.
The first phase after drinking is purging. Most people vomit, sometimes intensely, and diarrhea is also common. How severe the purging is depends partly on how well you followed the dietary preparation. Practitioners and participants alike treat this not as a side effect but as the medicine working, clearing out physical and emotional weight.
Once the purging subsides, the visionary phase begins. This is where the psychoactive effects peak: vivid closed-eye imagery, intense emotions, resurfacing memories, and experiences that participants frequently describe as spiritual or revelatory. Throughout this phase, the practitioner sings icaros, which are medicine songs believed to shape and direct the experience. Different songs carry different intensity. A practitioner may sing softly during calm stretches and shift to more powerful chants to move the group through difficult moments. Instruments like harmonicas, leaf rattles, and guitars accompany the singing. Participants often report that a new round of icaros can restart visions or emotional processing even when they thought the experience was winding down.
The final phase is grounding. As sunrise approaches, the music shifts to songs of celebration, forgiveness, and joy. The intensity fades, and participants gradually return to ordinary awareness. Many retreats hold a sharing circle the following morning.
The Preparation Diet
Preparation for a ceremony involves dietary and behavioral restrictions known as “la dieta.” The reason is partly pharmacological: because the brew contains compounds that block monoamine oxidase, eating foods high in tyramine (an amino acid found in aged, fermented, and cured foods) can cause a dangerous spike in blood pressure.
Most retreat centers recommend starting preparation at least three to five days before the ceremony, with two weeks being ideal. The restrictions tighten as the ceremony approaches:
- Two weeks before: No pork, alcohol, cannabis, recreational drugs, heavily processed foods, refined sugar, or hot spices. Sexual activity is also discouraged.
- One week before: No red meat, fermented foods (pickles, aged cheese, kombucha, soy sauce), caffeine, animal fats, or carbonated drinks.
- 24 hours before: No avocado, chocolate, broad beans, lentils, peanuts, sour cream, eggplant, figs, grapes, or pineapple. These are all higher in tyramine or other compounds that interact with the brew.
- Day of ceremony: No overripe fruit, dried fruit, eggs, dairy, garlic, tomatoes, spinach, or heavy sweets.
Physical Effects on the Body
Beyond the purging, ayahuasca produces measurable changes in the body. Systolic blood pressure typically rises, and higher doses can cause a significant increase in diastolic blood pressure as well. Heart rate may increase modestly. Pupils dilate, and body temperature can shift slightly. These cardiovascular effects are generally well tolerated in healthy people, but they matter significantly for anyone with heart conditions or high blood pressure. After the peak passes, heart rate and blood pressure tend to drop back down.
Dangerous Interactions With Medications
The most serious safety concern with ayahuasca is its interaction with medications that affect serotonin, particularly SSRIs and other antidepressants. Because the vine’s alkaloids block the same enzyme system that these drugs rely on, combining them can trigger serotonin syndrome, a potentially fatal condition in which serotonin builds to dangerous levels in the brain. Symptoms include high fever, seizures, muscle rigidity, and rapid heart rate. This interaction is not hypothetical or rare. It is a well-documented pharmacological conflict.
Other medications and substances that pose risks include other types of antidepressants (SNRIs, MAOIs, tricyclics), certain migraine medications, stimulants like amphetamines and MDMA, and some cough suppressants containing dextromethorphan. Most reputable retreat centers ask participants to stop SSRIs well in advance, often several weeks, because these drugs take time to fully clear the body.
Research on Depression
A randomized, placebo-controlled trial published in Psychological Medicine tested ayahuasca in people with treatment-resistant depression. By day seven after a single session, 64% of participants in the ayahuasca group showed a significant response on a standard depression scale, compared with 27% in the placebo group. The effect size was large and grew stronger over the week rather than fading. Remission rates (meaning symptoms dropped to minimal levels) trended toward significance: 36% for ayahuasca versus 7% for placebo. Interestingly, the depth of the mystical experience during the session, specifically feelings of transcending time and space, correlated with greater improvement in depression scores.
These findings are promising but still early. The trial was small, and ayahuasca is not an approved treatment for any condition in most countries. The results do, however, help explain why a growing number of people seek out ceremonies specifically for mental health reasons.
Integration After the Ceremony
What happens after the ceremony may matter as much as the ceremony itself. Integration is the process of making sense of the experience and translating whatever emerged into lasting changes in daily life. Without it, even powerful insights can fade within weeks.
Integration generally follows three stages: capturing a narrative of what happened (often through journaling or sharing circles the morning after), identifying themes and decoding the content, and then implementing concrete changes. Common integration practices include therapy (particularly approaches that work with internal parts or mindfulness), regular meditation, breathwork, dream journaling, and community involvement. Many people work with an integration therapist in the weeks following a ceremony, someone trained to help process psychedelic experiences without judgment. Others rely on peer support groups, either in person or online, where participants share their ongoing process of applying what they learned.
The goal is not to chase the experience itself but to let it inform how you live afterward: relationships, habits, self-understanding, and sense of purpose.