Also known as yage, the brew is made from a jungle vine (the ayahuasca) and a shrub called chacruna. It contains dimethyltryptamine (DMT), a powerful hallucinogen, and it's only legal in Peru as part of spiritual exercises. Though plenty of shamans are happy to cater to tourists who want to try it.
As one yaga experimenter and BBC writer described it, it's not a fun high the way ecstasy or cocaine might be. It makes you feel kind of gross, but you can have some powerful visions while it lasts. And like many hallucinogens, lots of users claim that the beneficial effects last for a long time afterward, treating everything from PTSD to drug addiction. Some researchers even think it might be good for diabetics.
And it can probably only kill you if it accidentally has nightshade in it, apparently.
As I said, the study was a preliminary one. There was no control group, so it could all be a placebo effect. Plus half of the patients vomited, which isn't exactly a great side effect rate. But this isn't the only trippy substance being pursued as a possible treatment for mental illness. Other researchers are hard at work investigating LSD and magic mushrooms to the same effect.
Want more science? Give these a click: