New study reveals people were getting high on this 4,000 years ago

By Stephen Beech

People were taking drugs to get high 4,000 years ago, reveals a new study.

Ancient tooth marks dating back to the Bronze Age are the earliest traces of people chewing psychoactive betel nuts, say scientists.

They explained that state-of-the-art techniques that "make the invisible visible" enabled them to unearth evidence of cultural practices which otherwise might have been lost in the archaeological record.

Betel nut chewing has been practiced in Southeast Asia for generations.

The plants contain compounds that enhance the consumer’s alertness, energy, euphoria and relaxation.

Chewing betel nuts usually results in dark, reddish-brown to black stained teeth.

But unstained teeth may not necessarily mean that people didn’t chew betel nuts.

Using the new method, an international team of researchers examined ancient dental plaque from Bronze Age Thailand and found the earliest evidence of betel nut chewing.

Study first author Dr. Piyawit Moonkham said: "We identified plant derivatives in dental calculus from a 4,000-year-old burial at Nong Ratchawat, Thailand.

“This is the earliest direct biomolecular evidence of betel nut use in South East Asia.”

Study senior author Dr. Shannon Tushingham, associate curator of anthropology at the California Academy of Sciences in the US, said: “We demonstrate that dental calculus can preserve chemical signatures of psychoactive plant use for millennia, even when conventional archaeological evidence is completely absent.

“In essence, we’ve developed a way to make the invisible visible - revealing behaviours and practices that have been lost to time for 4,000 years.”

More than 150 human burials have been unearthed since 2003 at Nong Ratchawat in central Thailand, dating back to the Bronze Age.

The team collected 36 dental calculus samples from six individuals for the study, published in the journal Frontiers in Environmental Archaeology.

Back in the lab, researchers removed tiny amounts of plaque from the samples and the chemical residues found therein underwent analysis.

They also used betel liquid samples they produced themselves to ensure psychoactive compounds could be reliably detected through their analysis and to understand the complex biochemical interactions between ingredients.

Dr. Moonkham, an anthropological archaeologist at Chiang Mai University, Thailand, said: “We used dried betel nut, pink limestone paste, Piper betel leaves, and sometimes Senegalia catechu bark and tobacco.

"We ground the ingredients with human saliva to replicate authentic chewing conditions.

“Sourcing materials and experimentally ‘chewing’ betel nuts to create authentic quid samples was both a fun and interesting process.”

The findings showed that three of the archaeological samples – all stemming from a molar of the same individual, dubbed Burial 11 – contained traces of arecoline and arecaidine.

Those organic compounds, found in betel nuts but also in plants such as coffee, tea, and tobacco, have pronounced physiological effects on humans.

That suggests that betel nuts were chewed as early as 4,000 years ago in Thailand, according to the research team.

Dr. Tushingham said: “The presence of betel nut compounds in dental calculus does suggest repeated consumption, as these residues become incorporated into mineralized plaque deposits over time through regular exposure."

The researchers say the absence of tooth-staining could be the result of different consumption methods.

It could also be down to post-consumption teeth cleaning practices, or post-mortem processes affecting stain preservation over 4,000 years.

While traces of betel nut chewing were found in samples from only one individual, the team say there is currently no proof that Burial 11 received special treatment or was of elevated social status or unique ritual significance compared to the other burials at Nong Ratchawat.

But the presence of stone beads as grave goods could provide hints as to the individual's identity.

The researchers say studying more individuals at Nong Ratchawat and other local sites to learn when and to whom such grave goods were given could provide valuable further evidence.

The team said the methods applied can be used to examine the remaining burials at Nong Ratchawat and at other sites.

Dr. Tushingham said: “Dental calculus analysis can reveal behaviours that leave no traditional archaeological traces, potentially revolutionising our understanding of ancient lifeways and human-plant relationships.

“It could open new windows into the deep history of human cultural practices.”

Dr. Moonkham added: “Understanding the cultural context of traditional plant use is a larger theme we want to amplify - psychoactive, medicinal, and ceremonial plants are often dismissed as drugs, but they represent millennia of cultural knowledge, spiritual practice, and community identity.

“Archaeological evidence can inform contemporary discussions by honoring the deep cultural heritage behind these practices.”