A large global survey of over 10,800 ayahuasca users from more than 50 countries found that acute physical adverse effects, primarily vomiting, occurred in 69.9% of participants, with 2.3% needing medical attention. Adverse mental health effects in the weeks or months after use were reported by 55.9% of the sample, but about 88% of those viewed these effects as part of a positive growth or integration process; around 12% sought professional support. Physical adverse effects were linked to older age at first use, having a physical health condition, higher lifetime and recent use, a prior substance use disorder diagnosis, and using ayahuasca in unsupervised settings.
Ayahuasca, a traditional Amazonian decoction, is being studied for mental health benefits, but its adverse effects are not well understood. An analysis of 10,836 participants from the Global Ayahuasca Survey found that 14.2% had a prior anxiety disorder and 19.7% a depressive disorder, yet their median mental health score (SF-12) was 50.16, comparable to the general population. A history of anxiety or depression was linked to more adverse mental states after use. However, experiences like visual distortions and higher ayahuasca use correlated with better mental health. Women reported more adverse states but no worsened mental health.