Yes, ayahuasca makes most people vomit. In clinical trials, roughly 70% of participants experienced nausea or vomiting. It’s so common that practitioners have their own word for it: “la purga,” or the purge. Understanding why it happens, what it feels like, and how long it lasts can help you know what to expect.
Why Ayahuasca Triggers Vomiting
The vomiting isn’t a side effect in the way a medication might upset your stomach. It’s a direct pharmacological response driven by serotonin, the same chemical messenger involved in the brew’s psychoactive effects. About 95% of the body’s serotonin is produced in the gut, and ayahuasca floods that system with compounds that activate serotonin receptors throughout the digestive tract and in a part of the brainstem called the chemoreceptor trigger zone, which acts as the body’s poison detector.
Two separate groups of chemicals in ayahuasca contribute to this effect. The first is DMT, the primary psychoactive compound, which binds to serotonin receptors linked to emesis. The second, and possibly more important for the vomiting specifically, is a group of compounds called harmala alkaloids (harmine, harmaline, and tetrahydroharmine) found in the Banisteriopsis caapi vine. A Phase 1 clinical study of pure oral harmine found that nausea and vomiting were the major dose-limiting effects, confirming that harmine on its own is enough to make people vomit. In other words, even without the psychedelic component, the vine base of ayahuasca would still cause nausea.
These harmala alkaloids stimulate serotonin-mediated vagal pathways, essentially sending urgent signals from the gut to the brain that something foreign has entered the body. Your body treats the brew as a mild toxin and responds accordingly. This mechanism likely evolved as a defense against poisoning.
What the Experience Is Like
The overall effects of ayahuasca last about four to six hours. Nausea typically builds during the first hour as the brew takes effect, and vomiting, when it happens, tends to occur in the early portion of the experience. It’s not usually a prolonged episode lasting hours. Many people describe one or several bouts of vomiting, sometimes accompanied by diarrhea, after which the nausea subsides and the psychological effects become more prominent.
The intensity varies. Some people experience mild queasiness that passes without vomiting. Others have forceful, repeated episodes. There’s no reliable way to predict which experience you’ll have, and the same person can have different reactions across separate sessions.
How Practitioners View the Purge
In indigenous Amazonian traditions, the vomiting isn’t seen as an unpleasant side effect to be minimized. It’s considered a central part of the experience. Indigenous cultures view the purge as a cleansing process, a physical release of emotional or spiritual weight. Many ceremony participants, even those from Western backgrounds, report feeling a sense of relief or lightness after vomiting, describing it as cathartic rather than merely unpleasant.
This framing shapes how retreat centers and ceremonial facilitators handle the experience. Buckets or designated areas are standard. Participants are generally told to expect vomiting and to lean into it rather than resist. The logic, from a traditional perspective, is that the body is expelling what it no longer needs.
Physical Risks of the Vomiting
For most healthy people, the vomiting is uncomfortable but not dangerous. However, there are real medical risks worth understanding. The most serious acute concern is aspiration, which means inhaling vomit into the lungs. This risk increases if someone is lying on their back, heavily sedated, or unable to control their body during an intense psychological experience. In a medical context, this is considered the primary danger of ayahuasca-induced vomiting.
Repeated or severe vomiting can also lead to dehydration and electrolyte imbalances. Case reports document serious complications following ayahuasca use that required intensive medical care including IV fluids and electrolyte monitoring. While these cases are uncommon (about 2.3% of reported adverse effects required medical attention), they underscore that the physical toll is not always benign. People with conditions affecting the esophagus, those prone to dehydration, or anyone taking medications that interact with serotonin pathways face higher risks.
Can You Prevent or Reduce It?
Most retreat centers recommend a restricted diet in the days leading up to a ceremony, sometimes called “la dieta.” This typically involves avoiding aged cheeses, cured meats, fermented foods, alcohol, and other items high in tyramine, an amino acid that can interact with the harmala alkaloids. Eating lightly or fasting for several hours before drinking is also standard advice. These practices may reduce the severity of nausea for some people, though they won’t eliminate it entirely since the vomiting is triggered by the brew’s chemical action on serotonin receptors, not by what’s already in your stomach.
Some people wonder about taking anti-nausea medication beforehand. This is complicated. Common over-the-counter options that block serotonin receptors could theoretically reduce nausea, but they might also interfere with the brew’s psychoactive effects or create unpredictable interactions. Many facilitators discourage it, both for pharmacological reasons and because they consider the purge an essential part of the process.
The most practical approach is accepting that vomiting is likely, staying well hydrated before and after, and making sure you’re in a setting where someone can help reposition you if needed during the experience. An empty stomach won’t stop the nausea, but it can make the vomiting less distressing.