Archaeologists find richest cache of ancient mind-altering drugs in South America

When José Capriles arrived in 2008 at the Cueva del Chileno rock shelter, nestled on the western slopes of Bolivia’s Andes, he didn’t know what he would find within. Sweeping aside layers of fresh and ancient llama dung, he found the remains of an ancient burial site: stone markers suggesting a body had once been interred there and a small leather bag cinched with a string. Inside was a collection of ancient drug paraphernalia—bone spatulas to crush the seeds of plants with psychoactive compounds, wooden tablets inlaid with gemstones to serve as a crushing surface, a wooden snuffing tube with a carved humanoid figure, and a small pouch stitched together from the snouts of three foxes.

Now, more than a decade later, Capriles—an anthropologist at Pennsylvania State University in State College—and colleagues have discovered that the 1000-year-old bag contains the most varied combination of psychoactive compounds found at a South American site, including cocaine and the primary ingredients in a hallucinogenic tea called ayahuasca. The contents suggest the users were well versed in the psychoactive properties of the substances, and also that they sourced their goods from well-established trade routes.

“Whoever had this bag of amazing goodies … would have had to travel great distances to acquire those plants,” says Melanie Miller, lead author of a new study on the discovery and a bioarchaeologist at the University of Otago in Dunedin, New Zealand. “[Either that], or they had really extensive exchange networks.”

Nearly every culture on Earth has dabbled with consciousness- and perception-altering substances. Indigenous groups from Central and South America have used hallucinogens such as peyote and psilocybin mushrooms during rituals and religious ceremonies for thousands of years. Archaeologists have uncovered hundreds of items that provide a glimpse into these ancient practices, but few are as complete as the Bolivian find.

In 2010, Miller joined the team to help chemically analyze the items, which had been nearly perfectly preserved in the arid conditions of the 4000-meter-high mountains. Radiocarbon dating revealed that the outer bag was made around 1000 C.E. Next, Miller carefully unwound the fox snout pouch and emptied its dust and debris onto a piece of aluminum foil. Using a technique frequently used in modern illicit drug testing called liquid chromatography tandem mass spectrometry, she and her fellow researchers hunted for chemical signatures in the sample. They identified at least five psychoactive substances: cocaine, benzoylecgonine, bufotenine, harmine, and dimethyltryptamine.

Harmine and dimethyltryptamine are the main ingredients in ayahuasca, used ceremonially for centuries by indigenous South Americans. Miller says their presence alongside the snuffing tube and tablet may mean that people inhaled these chemicals long before they were brewed into a beverage.

The mixture’s origins also offer clues to the trade routes of the people who occupied the high plains. Several of the compounds come from the plant genus Anadenanthera—also known as vilca, cebil, or yopo—which grows widely through South America, but not in this region of the Andes. Similarly, the likely source of the harmine is a lowland Amazonian species.

Miller says it’s possible that the mixture of compounds was unique to the region. The fact that at least two of the ingredients are known to be used in tandem in ayahuasca raises the possibility that this shaman was selecting plant combinations for specific mind-altering effects, they report today in the Proceedings of the National Academy of Sciences . “Maybe they were mixing multiple things together because they realized when they’re combined, they have a whole different set of experiences,” Miller says.

When indigenous South Americans began to brew ayahuasca is still a major mystery, says Christine VanPool, an anthropologist at the University of Missouri in Columbia who wasn’t involved in the work. She’s intrigued by the idea they may first have discovered its properties by inhaling its key compounds. Shamans “say they’ve had [ayahuasca] for a very long time. So in some ways, I wasn’t surprised,” she says. But because archaeological evidence has been lacking, the new find is “exciting.”