Archaeologists are hailing the discovery of an "extraordinary cache" of cannabis found in an ancient burial in northwest China, saying that the unique find adds considerably to our understanding of how ancient Eurasian cultures used the plant for ritual and medicinal purposes.

In a report in the journal Economic Botany, archaeologist Hongen Jiang and his colleagues describe the burial of an approximately 35-year-old adult man with Caucasian features in China's Turpan Basin. The man had been laid out on a wooden bed with a reed pillow beneath his head.

View Images In an unprecendented discovery, the ancient cannabis plants were discovered in a complete and well-preserved state. Photograph courtesy Hongen Jiang

Thirteen cannabis plants, each up to almost three feet long, were placed diagonally across the man's chest, with the roots oriented beneath his pelvis and the tops of the plants extending from just under his chin, up and alongside the left side of his face. (Read how Eurasian gold artifacts tell the tale of drug-fueled rituals.)

Radiocarbon dating of the tomb's contents indicates that the burial occurred approximately 2,400 to 2,800 years ago.

This discovery adds to a growing collection of archaeological evidence showing that cannabis consumption was "very popular" across the Eurasian steppe thousands of years ago, says Jiang.

A Truly Unique Burial

The burial is one of 240 graves excavated at the Jiayi cemetery in Turpan, and is associated with the Subeixi culture (also known as the Gushi Kingdom) that occupied the area between roughly 3,000 to 2,000 years ago. At the time, Turpan's desert oasis was an important stop on the Silk Road.

Cannabis plant parts have been found in a few other Turpan burials, most notably in a contemporaneous burial in nearby Yanghai cemetery discovered nearly a decade ago, which contained close to two pounds of cannabis seeds and powdered leaves.

However, this is the first time ever that archaeologists have recovered complete cannabis plants, as well as the first incidence of their use as a "shroud" or covering in a human burial, says Jiang.

Locally Grown

Since previous cannabis finds in Turpan burials consisted only of plant parts, it has been difficult for researchers to determine whether the plant was grown locally or obtained through trade with neighboring regions.

The plants in the Jiayi burial, however, were found lying flat on the man's body, leading archaeologists to conclude that the cannabis had been fresh—and therefore local—when it was harvested for the burial.

In addition, while nearly all of the flowering heads of the 13 female plants had been cut off before they were placed on the body, a few that remained were nearly ripe and contained some immature fruit, suggesting that the plants were collected—and that the burial occurred—in late summer.

View Images A detail from one of the ancient cannabis plants, showing the resinous "hairs" that contain psychoactive compounds. Photograph courtesy Hongen Jiang

Prized for Psychoactive Qualities

The other question that archaeologists grapple with when they encounter cannabis is the purpose of its presence. This multipurpose plant has been valued not only for its psychoactive properties, but also for its durable hemp fibers, which could be woven into cloth, as well as its nutritious, oil-rich seeds.

However, no hemp textiles have been found in Turpan burials, and the seeds of the plants in the Jiayi burial are too small to serve as a practical food source, archaeologist Jiang notes.

Meanwhile, the flowering heads of the Jiayi plants were covered with glandular trichomes, a sort of tiny plant "hair" that in cannabis secretes resin containing psychoactive cannabinoids such as THC. The researchers suspect that this marijuana was grown and harvested for its psychoactive resin, which may have been inhaled as a sort of incense or consumed in a beverage for ritual or medicinal purposes.