Oldest evidence of cannabis smoking found in ancient Chinese cemetery

Cannabis is a surprisingly versatile plant—so versatile that Yang and his colleagues say ancient people domesticated it at least twice, for very different reasons.Although cannabis has turned up at other sites, from Western China to the Altai Mountains in Siberia, archaeologists have never found such direct indications that ancient people were lighting it up. Yang and his colleagues’ chemical analysis found that the cannabis plants burned at the cemetery had been very high in THC, which makes them different from domesticated hemp plants and from most of the wild cannabis that grows on hillsides from the Caucasus to Western China.Plants that produce more THC tend to produce less CBD, and vice versa. “Humans are always going to be looking for wild plants that can have effects on the human body, especially psychoactive effects, so if there were wild varieties with high THC levels, they would have been readily targeted,” said co-author Robert Spengler, laboratory director at the Max Planck Institute for the Science of Human History.At the moment, Yang and his colleagues don’t have enough evidence to say whether the plants here were domesticated or gathered, but they can say that by 2,500 years ago, people were smoking cannabis as a ritual drug in Western China.