Ayahuasca is a traditional South American medicine brewed from a combination of several plants that are legally available. Ayahuasca contains the potent hallucinogen DMT as well as harmaline, an alkaloid that allows DMT to quickly cross the blood-brain barrier. Unlike the short-lived effects of ingesting DMT in a pure form, ayahuasca intoxication can last up to 10 hours. While many take ayahuasca for its vivid and realistic hallucinations and the promise of insight into the mysteries of the mind, some are unprepared for the negative side effects of ayahuasca. These intense side effects virtually guarantee that ayahuasca will never be a popular psychedelic drug.

Nausea and Vomiting

The most reported side-effect of ayahuasca is nausea, followed by intense repetitive vomiting. For some, the vomiting comes early, while for others it occurs during the hallucinations. In ritual settings in South America, vomit buckets are often close at hand for this certainty, according to National Geographic writer Kira Salak in her 2004 article “Peru: To Hell and Back." Some users experience diarrhea as well. In the shamanic cultures where ayahuasca originated, these gastro-intestinal events are considered signs that the medicine is cleansing the body, mind and soul of impurities and toxins.

Other Physical Side Effects

Some users experience profuse sweating, tremors, increased blood pressure and heart rate, according to Peter Strafford, author of the “Psychedelics Encyclopedia.” These effects are most likely due to DMT intoxication, which is also known in a pure state to cause hypertension, agitation, dilated pupils, dizziness and muscular incoordination. Neither ayahuasca, nor DMT, are addictive.

Emotional Intensity

Ayahuasca, like other hallucinogens such as LSD and psilocybin, can sir up profound emotional states, including anxiety, fear and paranoia while, at the same time, providing profound depersonalization, so that the user may be more receptive to emotionally charged memories and past traumas. This profound and unsettling effect has attracted medical doctors to research the psychiatric value of ayahuasca. However, if ayahuasca is not taken in a safe environment with trained guides, these effects could be destabilizing. In the 2004 National Geographic article “Peru: To Hell and Back,” ayahuasca expert Charles Grob, M.D., warns, "Ayahuasca is not for everyone. You have to be willing to have a very powerful, long, internal experience, which can get very scary.”

Taken in a ritual context, such as provided in ayahuasca shamanism or part of the Brazilian ayahuasca church União do Vegetal, ayahuasca use appears safe and may even facilitate greater psychological health for Brazilian youth, according to a 2005 study published in the “Journal of Psychiatric Drugs.”