Cannabis was a staple part of the diet in the ancient Chinese Tang dynasty (618-907), according to a new archaeological study in central China. It is widely known that ancient Chinese cultivated and also consumed cannabis seeds in a kind of porridge. Many Chinese historical texts suggested that the plant was an important source of food, but archaeological evidence supporting the written accounts was scant. The discovery confirmed that in a period when the Chinese civilisation reached its peak, cannabis was a source of not only mental stimulus, clothing and medicine, but also nutrition, according to the researchers. The discovery was made during works at a primary school playground in Taiyuan, Shanxi province, in 2019, when construction workers unearthed a tomb. For 1,320 years, the tomb was not disturbed, with wall paintings and artefacts almost perfectly preserved in the unusually dry chamber. In one of the jars holding staple food, the researchers found remnants of cannabis, with some seeds still showing their original colour. The ancient seeds were nearly twice as big as normal, suggesting they were not the same as a typical cannabis plant today. The researchers believed that they belonged to Cannabis sativa , a species that originated in central Asia with lower concentrations of the psychoactive substance tetrahydrocannabinol (THC) than the modern marijuana, which is a more potent hybrid of sativa and indica. The tomb belonged to Guo Xing, a cavalry captain who had fought with Tang emperor Li Shimin, or Taixzong, in a series of bloody battles on the Korean peninsula. “The cannabis was stored in a pot on the coffin bed amid other staple grains such as millet. Obviously, the descendants of Guo Xing buried cannabis as an important food crop,” Jin Guiyun, a professor with the school of history and culture at Shandong University, said in a paper published in the domestic peer-reviewed journal Agricultural Archaeology last month. Procession of cannabis is a criminal offence in China today and a conviction for drug dealing can result in a death sentence. But for people living in the heartland of the powerful Tang empire, cannabis could be more important than rice, according to Jin and her colleagues. Taiyuan was warmer and wetter in the Tang dynasty than today and rice was cultivated in the wider Yellow River region. But the Guo family did not put any rice in the tomb. The researchers said this might have reflected the personal diet of the veteran soldier, who died aged 90. “The cannabis was buried as food for the tomb owner’s feast and health in the afterlife,” they added. Cannabis was first domesticated 12,000 years ago in China, say researchers The researchers also noticed that cannabis seeds’ husks were not removed. The husk does not taste good, but contains a higher level of THC. “Cannabis seeds with husks are not only related to the high lignin content of the husk and its hard texture, which can reduce the chance of mould and prolong the storage time, it may also stimulate the nerves and cause hallucinations due to the consumption of husk for religious and medical purposes,” Jin and co-authors with the Taiyuan Municipal Institute of Archaeology said in the paper. In ancient Chinese texts, cannabis was referred to as one of the wu gu , or five staple food crops. Eating too much unhusked cannabis seeds could “make a person run about like mad”, according to the Compendium of Materia Medica , a book written by herbalist Li Shizhen about 500 years ago. Since the 1980s, Chinese archaeologists have found and identified cannabis remnants in tombs all over China dating as far back as 6,600 years ago. But the plant was mostly explained as a ritual item used to generate hallucinations in a religious event. China has banned marijuana since the 1950s. Most Chinese history textbooks today refer to the mass plantation of cannabis in ancient China as an economic activity to produce textiles for clothing. Hu Jiang, associate professor of criminal law with Southwest University of Political Science and Law in Chongqing, said the loosening of controls on cannabis consumption across the globe had put enormous pressure on China to maintain its strict crackdown policies. In 2020, the United Nations removed cannabis from its drug control list because the plant was less harmful and had more medicinal benefits than previously thought. The legalisation of “recreational marijuana” in other countries “greatly increases the opportunities for our citizens to come into contact with and use marijuana products out of curiosity”, said Hu and his colleagues in a paper published in the Journal of Criminal Investigation Police University of China last month. In recent years, the Chinese government allowed farmers to plant some “safe” cannabis species with low THC but high cannabidiol, a compound that has a soothing effect but is not addictive. While the global cultivation of cannabis plants has shrunk by more than 90 per cent since the 1960s, the plantation area in China – mostly for hemp fibre – has increased more than 30 per cent in just a year to 24,400 hectares (60,300 acres) by the end of 2019, according to the government data. The use of new cultivation technology also increased productivity by more than three times to 5.2 tonnes per in the same period.