The Oldest Drug Habit on Record Is Betel Nut, Sucked by Foragers in Sulawesi Up to 25,000 Years Ago

About one person in ten alive today chews betel, a quid of areca nut, slaked lime and betel leaf that stains the mouth red and delivers a mild stimulant called arecoline; after caffeine, alcohol and nicotine it is the most used psychoactive substance in the world. A paper published in Science Advances on 9 September, and which we are a week late to, argues that the habit is at least 16,000 years old and possibly 25,000, which would make it the earliest recorded use of any drug by human beings. The previous record, 13,000-year-old traces of beer brewing at a burial site in Israel, falls by at least three millennia.

The teeth

The evidence comes from two individuals excavated at separate sites in South Sulawesi, Indonesia, one dated to between 25,000 and 16,000 years ago and the other to between 7,600 and 6,300. Both had grooves worn into their teeth that the team, led by the archaeologist Adam Brumm of Griffith University, could not account for by diet, tools or fibre-working. "We couldn't explain them," Brumm told the ABC. What matched them was the pattern left by habitually holding a fibrous areca nut against the teeth and sucking it, a practice still found in parts of the region and reflected in the paper's title: "Betel Nut Sucking is the Earliest Recorded Evidence for the Habitual Use of a Neuroactive Plant Drug".

The chemistry

Wear alone would not have carried the claim, so the team looked for the molecule. Residue analysis of the teeth identified arecoline. To show it was present at a meaningful dose rather than a trace, the researchers soaked betel nuts in artificial saliva to reproduce what a mouth would extract, then applied that saliva to frog egg cells engineered to express human brain receptors, and recorded the response. The point of the experiment was to demonstrate that the amount released by sucking, as opposed to chewing a prepared quid, is enough to act on the nervous system. Brumm's guess at the motive is the one modern users give: the numbing warmth. "I suspect that was the effect that they were after."

What outsiders say

Sofia Samper Carro, an archaeologist at the Australian National University who was not involved, told the ABC that "the early evidence of drug consumption presented here predates any published evidence by thousands of years". Her caveat, which Brumm shares, is that the practice is probably older still and simply hard to find: a habit that leaves its trace in tooth wear and a fragile alkaloid will survive in very few skeletons, and Sulawesi's caves are unusually kind to bone. The dating range on the older individual is wide, and the honest headline is 16,000 years with 25,000 possible, rather than 25,000 flat. Areca palms are native to the region, and the finding fits what is known of Sulawesi as an early centre of behavioural complexity; the island holds the world's oldest known figurative cave art, at more than 51,000 years.

Why it matters beyond the record

Betel is not a harmless heirloom. The International Agency for Research on Cancer classes areca nut as a Group 1 carcinogen, and oral cancer rates in Papua New Guinea, Taiwan and parts of India track its use closely; public-health campaigns across the Pacific have spent two decades trying to reduce it. The discovery that the habit predates agriculture, pottery and the domestication of any animal explains something about why those campaigns are hard. Humans on this island were seeking out a psychoactive plant, and modifying their own bodies to use it, before they had learned to farm. The paper is at Science Advances; the CNN, Technology Networks and SciTechDaily write-ups all carry the same figures.