Marijuana can linger in the human system for a few months at most, but cannabis residue will stick to other surfaces for millennia. High up in the Pamir Mountains, in what is now western China, archaeologists were excavating the tombs of Jirzankal Cemetery when they came upon a set of braziers and asked themselves what purpose the tools served. After analyzing the residue, a team of researchers found that it not only came from cannabis, but contained unusually high levels of THC—the compound that gives cannabis its psychoactive, or mind-altering, qualities.
Indeed, these braziers, or wooden incense burners, mark some of the earliest, most robust physical evidence of humans burning cannabis specifically for its psychoactive effects. Researchers from China and Germany described their findings in a study published today in the journal Science Advances.
One of the most compelling pieces of evidence pointing to the use of psychoactive cannabis in ancient Central Asia is purely textual: a section in Herodotus’s Histories about the Scythians, who, after funerals, would “throw the seed … upon the red-hot stones” and “shout for joy” as the vapor rose. But archaeological evidence has been harder to come by. While excavating temples in Turkmenistan, the famed archaeologist Viktor Sarianidi reignited interest in the region’s ancient drug culture when he claimed to have found ritual plant remains inside ceramic vessels, which could have been used for drinking the hallucinogenic soma. Similar ceramics, however, have since been identified elsewhere in the region as cheese strainers, and later tests found that the ceramics did not actually hold remains of the ingredients originally reported. In fact, they did not contain plant remains at all—only plant impressions. And while a major 2006 study confirmed the presence of cannabis seeds in another ancient Chinese tomb, there was no evidence of burning or smoking the plant. The debate surrounding ancient drug use in Central Asia has been “extremely … I guess lively is the best way to put it,” Robert Spengler, a co-author of the new study and an archaeobotanist at Germany’s Max Planck Institute for the Science of Human History, told reporters.