Primitive pot: Earliest evidence of cannabis smoking discovered from residue in ancient incense burners

BEIJING — A new study reveals the discovery of the earliest hard evidence of cannabis being used specifically for its psychoactive compounds, according to a team of international scientists.

Researchers from the Chinese Academy of Social Sciences and the Max Planck Institute for the Science of Human History studied the residue found in rudimentary incense burners from ancient burial sites in the Pamir Mountains in western China. In addition to discovering signs of ancient marijuana, the study also shows some of the first signs of purposeful cultivation of higher tetrahydrocannabinol (THC) plants.

Earliest evidence of cannabis discovered
This is a typical brazier and burnt stones in ancient Pamirs. (Photo credit: WU Xinhua)

Cannabis cultivation has a long and storied history in East Asia, where the plant’s oily seeds and fiber have been harvested since 4000 BC. Though it’s one of the most widely used psychoactive drugs in the world now, there is little archaeological or historical evidence for ancient people using cannabis.

“The findings support the idea that cannabis plants were first used for their psychoactive compounds in the mountainous regions of eastern Central Asia, thereafter spreading to other regions of the world,” says Nicole Boivin, director of the Department of Archaeology at the Max Planck Institute for the Science of Human History, in a media release.

The archeology team identified psychoactive compounds preserved in incense burners (braziers) used 2,500 years ago at the site of the Jirzankal Cemetery in the eastern Pamir Mountains. This proved that the people there were purposefully selecting and breeding plants with higher levels of THC and burning them as a part of their funeral rituals.

The research team used what’s known as gas chromatography-mass spectrometry to identify and isolate the compounds preserved in the wooden braziers that were found by Chinese Academy of Social Sciences archaeologists.

Under analysis, the ancient incense burners contained compounds which, when isolated, were found to match exactly with the chemical signature of cannabis. The researchers also determined that the chemical signature signified higher levels of THC in the cannabis plants than what can be found in the wild.

“The exchange routes of the early Silk Road functioned more like the spokes of a wagon wheel than a long-distance road, placing Central Asia at the heart of the ancient world,” says Robert Spengler, the lead archaeobotanist for the study, also at the Max Planck Institute for the Science of Human History. “Our study implies that knowledge of cannabis smoking and specific high chemical-producing varieties of the cannabis plant were among the cultural traditions that spread along these exchange routes.”

The study was published in the journal Science Advances.