Ayahuasca: Benefits, Risks and Implications for Psychedelic Therapy

The hallucinogenic beverage ayahuasca has been used for religious and medicinal purposes by Amazonian tribes for thousands of years. More recently, ayahuasca retreats and research projects –  exploring the beverage’s potential effects on health, spirituality and personal growth – have seen its use expand globally.

Scientists are increasingly interested in ayahuasca’s effects on the brain and its potential role in psychedelic therapy. Yet alongside claims of profound transformation, reports of unpleasant and sometimes concerning side effects raise questions about its safety.

How ayahuasca affects the brain

Research using neuroimaging and spectroscopy shows that ayahuasca increases activity in brain regions associated with emotion, memory and self-awareness. Functional MRI studies suggest reduced activity in the brain’s default mode network, similar to effects observed with psilocybin and LSD.

The interaction of DMT with serotonin (5-HT2A) receptors is thought to drive its hallucinogenic and mood-altering properties. Beta-carbolines may add further complexity by modulating neurotransmission and neurogenesis.

Credit: iStock.

The Global Ayahuasca Project

At the University of Melbourne, Dr. Daniel Perkins is involved in a number of research projects surrounding medicinal psychedelics and medicinal cannabis. He is the director of the Global Ayahuasca Project, which aims to increase our understanding of ayahuasca drinking context across the world, including why people drink it, the reported impacts of ayahuasca on health and wellbeing and the potential risks associated.

Perkins and his team analyzed data from an online Global Ayahuasca Survey that ran from 2017–2019, recruiting 10,836 respondents from over 50 countries.

The questionnaire obtained demographic information, such as age, sex, level of education and history of mental health diagnoses, and data relating to ayahuasca drinking history, such as frequency, patterns and contexts of use. Participants were asked to report any acute adverse physical effects via a checkbox system, and a subsequent question asked whether they had ever experienced any medium-term mental health, emotional or perceptual changes in the weeks or months following ayahuasca ceremonies or sessions.

Responders for whom the “adverse effects” section of the questionnaire was not complete were excluded from the final analyses. In total, Perkins and teams’ study included 8,216 responses for the adverse physical effects section of the questionnaire, and 7,839 responses for the adverse mental effects section. Approximately 46% of the participants were female, with an average age of 40 years and over.

Physical side effects of ayahuasaca

Acute physical health adverse effects were reported by 69.9% of the sample (Table 1).

Table 1.  The most common physical side effects reported by users of ayahuasca.

The researchers emphasize that vomiting and nausea are considered a “normal” effect of ayahuasca for experienced users: “In the case of traditional ayahuasca ceremonies and even in non-traditional ceremonies, not only is vomiting/nausea not considered an adverse effect, but it is even sought out for its purging and perceived spiritual cleansing benefits,” they write in the paper.

Approximately 2.3% of the participants reported that they required medical attention for any adverse effects. “These results are consistent with previous studies, with regular users reporting that most adverse physical effects seem to not be serious and do not compromise health,” Perkins and colleagues explain.

Several factors were more likely to be associated with adverse events occurring, including:

• A higher use of ayahuasca in the previous year or lifetime
• The age of participants – those who were older when they first drank ayahuasca were more likely to experience adverse events
• Physical health conditions
• Comorbidity anxiety disorder
• Previous diagnosis of a substance use disorder
• Use of ayahuasca in a non-supervised context

Mental health and emotional side effects

Mental health or emotional challenges were reported by 55% of participants, a “relatively high” figure according to the researchers. These ranged from perceptual distortions to psychological discomfort.

• Hearing or seeing things others did not (hallucinations): 28.5%
• Feelings of disconnection or loneliness: 21%
• Visual distortions: 4.4%

The duration of any adverse mental health effect reported in the survey was less than one week. When asked to offer qualitative perspectives on these experiences, some of the participants expressed how they are considered a positive element of their ayahuasca journey.

Ayahuasca is not just a pharmacological experience – it is considered a spiritual practice in its tradition. “In the context of such experiences, it is not surprising that a process of psychological integration and assimilation may be required,” Perkins and colleagues note.

“I have had numerous experiences where ayahuasca has brought difficult patterns into my awareness in my daily life, which is never comfortable but always results in growth in the end,” – an anonymized quote from one of the survey participants.

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Ayahuasca drinking history variables were not significantly associated with adverse mental health effects. “This finding, while intriguing, is in accordance with the early age of ayahuasca initiation in traditional contexts, both Indigenous and in ayahuasca churches, where researchers failed to find long-term neuropsychiatric alterations,” the authors note. Previous work by Dr. José Carlos Bouso, director of the International Center for Ethnobotanical Education, Research, and Service and a co-author of the paper, also found that long-term use of ayahuasca was associated with a higher positive perception of health or with a healthy lifestyle.

Is ayahuasca safe?

The question “is ayahuasca safe?” does not have a simple answer. While many users report profound benefits, the survey demonstrates that adverse effects are common. The key considerations are:

• Severity: Most side effects are mild and temporary, but a small proportion may require medical intervention.
• Context: Traditional ceremonies often include trained facilitators and structured integration, which may reduce risks compared to unsupervised use.
• Vulnerability: Individuals with pre-existing psychiatric or physical health conditions may face greater risks.

Unlike prescription drugs, ayahuasca’s safety profile cannot be evaluated solely by clinical parameters. Cultural, psychological and spiritual contexts shape both the risks and perceived benefits.

Implications for global health

There are limitations to the study design that must be acknowledged and could limit its validity, including its reliance on self-reported data gathered in a retrospective nature. However, the large sample size makes this work “the most important source of information regarding ayahuasca’s adverse effects” to date, in the research team’s opinion. But what does this resource tell us? It appears that ayahuasca has notable – though rarely severe – side effects on both physical and mental health, which have implications for public health: “In that sense, ayahuasca practices can hardly be assessed with the same parameters used for prescription medicines,” the authors say, “since the myriad of its effects include challenging experiences that are intrinsic to the experience, some of which are considered as part of its healing process.”

“Many are turning to ayahuasca due to disenchantment with conventional Western mental health treatments; however, the disruptive power of this traditional medicine should not be underestimated, commonly resulting in mental health or emotional challenges during assimilation. “While these are usually transitory and seen as part of a beneficial growth process, risks are greater for vulnerable individuals or when used in unsupportive contexts,” the researchers conclude.

Ayahuasca occupies a unique position at the intersection of culture, spirituality and science. While widely reported to promote psychological growth and healing, it also carries a high prevalence of side effects, most commonly nausea, vomiting and temporary emotional challenges.

For researchers and clinicians, the key lesson is that ayahuasca cannot be disentangled from its context. Its risks and benefits extend beyond pharmacology to include ceremonial frameworks, personal vulnerability and cultural interpretation.

As psychedelic therapy moves further into mainstream science, ayahuasca provides a case study in both the promise and the complexity of harnessing traditional medicines in modern health care.

This content includes text that has been generated with the assistance of AI. Technology Networks' AI policy can be found here.