Dr Michelle Muscat

Ayahuasca is a psychedelic Amazonian ceremonial decoction or ‘liana of the soul’ containing Banisteriopsis caapi vine having alkaloids that cause monoamine oxidase inhibition. Another typical component is Psychotria viridis which contains dimethyltryptamine (DMT). The exact nature of the admixture brew may vary from place to place. Ayahuasca has also moved from shamans to recreational usage. There are both known religious and recreational uses for this herbal brew. It has hallucinogenic effects; the brew can induce out-of-body experiences and alter a person’s state of consciousness. These effects stem from ayahuasca’s effect on the serotonergic system.

The participation in ayahuasca rituals has been investigated by various authors. Studies specifically looked into the potential use of ayahuasca in cases of treatment-resistant depression, where it showed potential antidepressant properties.1-3 Different authors proposed other therapeutic uses, such as in mindfulness training,4 emotional regulation,5 eating disorders6 and it has also been hypothesised as potentially useful against traumatic memories7 and specific cases of drug dependence.8,9 In 2019, Ona et al. boldly reported that the prolonged controlled use of ayahuasca could have a positive effect on the QoL and psychological well-being of users.10 Another study which included 22 participants and assessed biochemical parameters in the setting of chronic ritualistic ayahuasca use, twice monthly or more for the minimum of one year, did not demonstrate derangements in hepatic function.11 Nonetheless, ayahuasca usage is inherently associated with vomiting, amongst other non-entheogenic reported effects. The vomiting is caused primarily from the effects on area postrema, found in the medulla oblongata, which controls vomiting.

It is of note that specific drug interactions may result in serious adverse effects; one such example is the serotonin syndrome which arises when ayahuasca is combined with SSRIs.12

Although various papers have put forth different uses for ayahuasca, on the other hand biomedical research investigating discriminative learning in zebrafish has shown that prolonged exposure to low concentrations may indeed cause harmful effects to learning and memory processes.13 Another concern relates to possible mutagenic effects.14 Furthermore, rat models have demonstrated foetal developmental toxicity.15,16

These are just some of the documented effects. Further studies into the neuroscience and neurophysiology behind ayahuasca may yield a more precise risk-benefit analysis.17-19


  1. Palhano-Fontes F, Barreto D, Onias H, et al. Rapid antidepressant effects of the psychedelic ayahuasca in treatment-resistant depression: a randomized placebo-controlled trial. Psychological medicine. 2019;49(4):655-63.
  2. Galvao ACM, de Almeida RN, Silva E, et al. Cortisol Modulation by Ayahuasca in Patients With Treatment Resistant Depression and Healthy Controls. Frontiers in psychiatry. 2018;9:185.
  3. da Silva FS, Silva EAS, Sousa GM, et al. Acute effects of ayahuasca in a juvenile non-human primate model of depression. Revista brasileira de psiquiatria. 2019;41(4):280-8.
  4. Soler J, Elices M, Dominguez-Clave E, et al. Four Weekly Ayahuasca Sessions Lead to Increases in “Acceptance” Capacities: A Comparison Study With a Standard 8-Week Mindfulness Training Program. Frontiers in pharmacology. 2018;9:224.
  5. Dominguez-Clave E, Soler J, Pascual JC, et al. Ayahuasca improves emotion dysregulation in a community sample and in individuals with borderline-like traits. Psychopharmacology. 2019;236(2):573-80.
  6. Renelli M, Fletcher J, Tupper KW, et al. An exploratory study of experiences with conventional eating disorder treatment and ceremonial ayahuasca for the healing of eating disorders. Eating and weight disorders : EWD. 2018.
  7. Inserra A. Hypothesis: The Psychedelic Ayahuasca Heals Traumatic Memories via a Sigma 1 Receptor-Mediated Epigenetic-Mnemonic Process. Frontiers in pharmacology. 2018;9:330.
  8. Nunes AA, Dos Santos RG, Osorio FL, et al. Effects of Ayahuasca and its Alkaloids on Drug Dependence: A Systematic Literature Review of Quantitative Studies in Animals and Humans. Journal of psychoactive drugs. 2016;48(3):195-205.
  9. Brierley DI, Davidson C. Developments in harmine pharmacology–implications for ayahuasca use and drug-dependence treatment. Progress in neuro-psychopharmacology & biological psychiatry. 2012;39(2):263-72.
  10. Ona G, Kohek M, Massaguer T, et al. Ayahuasca and Public Health: Health Status, Psychosocial Well-Being, Lifestyle, and Coping Strategies in a Large Sample of Ritual Ayahuasca Users. Journal of psychoactive drugs. 2019;51(2):135-45.
  11. Mello SM, Soubhia PC, Silveira G, et al. Effect of Ritualistic Consumption of Ayahuasca on Hepatic Function in Chronic Users. Journal of psychoactive drugs. 2019;51(1):3-11.
  12. Callaway JC, Grob CS. Ayahuasca preparations and serotonin reuptake inhibitors: a potential combination for severe adverse interactions. Journal of psychoactive drugs. 1998;30(4):367-9.
  13. Lobao-Soares B, Eduardo-da-Silva P, Amarilha H, et al. It’s Tea Time: Interference of Ayahuasca Brew on Discriminative Learning in Zebrafish. Frontiers in behavioral neuroscience. 2018;12:190.
  14. Kummrow F, Maselli BS, Lanaro R, et al. Mutagenicity of Ayahuasca and Their Constituents to the Salmonella/Microsome Assay. Environmental and molecular mutagenesis. 2019;60(3):269-76.
  15. da Motta LG, de Morais JA, Tavares A, et al. Maternal and developmental toxicity of the hallucinogenic plant-based beverage ayahuasca in rats. Reproductive toxicology. 2018;77:143-53.
  16. dos Santos RG. Safety and side effects of ayahuasca in humans–an overview focusing on developmental toxicology. Journal of psychoactive drugs. 2013;45(1):68-78.
  17. McKenna D, Riba J. New World Tryptamine Hallucinogens and the Neuroscience of Ayahuasca. Current topics in behavioral neurosciences. 2018;36:283-311.
  18. Bauer IL. Ayahuasca: A risk for travellers? Travel medicine and infectious disease. 2018;21:74-6.
  19. Tupper KW. The globalization of ayahuasca: harm reduction or benefit maximization? The International journal on drug policy. 2008;19(4):297-303.