Archaeological research has uncovered what may be the earliest known evidence of human drug use, tracing the habit to ancient foragers in Indonesia who sucked on psychoactive betel nuts as far back as 25,000 years ago. This finding predates previous records of prehistoric drug consumption, which centered on fermented beverages from about 13,000 years ago.

The discovery stems from the analysis of two rare human skeletons found on Sulawesi, an Indonesian island. One skeleton dates between 16,000 and 25,000 years old, while the other is approximately 7,000 years old. Both adults exhibited pronounced dental wear characterized by deep, rounded grooves on their teeth, some sufficiently severe to expose the inner dental pulp. This unusual wear pattern suggested habitual suction of hard, abrasive objects.

Researchers, led by Professor Adam Brumm of Griffith University’s Australian Research Centre for Human Evolution, proposed that these wear marks were caused by perpetually sucking on betel nuts, the seeds of the Areca catechu palm, which are traditionally chewed within betel vine leaves. Today, betel nuts are recognized as the fourth most widely used psychoactive substance globally, following alcohol, caffeine, and nicotine.

Chemical residue analysis of the skeletons’ teeth revealed traces of arecoline, the main psychoactive compound in betel nuts, supporting the theory of consistent use. Experiments conducted by the team showed that soaking betel nuts in artificial saliva released enough arecoline to induce a mild psychoactive effect, even without the slaked lime often added by modern users to intensify the high.

The habitual sucking likely produced a bitter and numbing sensation, which researchers suggest might have functioned as a traditional remedy for toothache. However, prolonged use appears to have caused severe dental damage, including pulp exposure and increased risk of infection. This cycle may have led to continuous use of the nuts to alleviate the pain they themselves caused.

While humans have long interacted with mind-altering plants and substances, this evidence represents the earliest direct indication of psychoactive plant use. Dr. Elisa Guerra-Doce, a European prehistory expert, noted the significance of the findings for establishing a millennia-old tradition of betel nut consumption, widespread in the Asia-Pacific region.

Previously, evidence of prehistoric drug use focused on alcoholic fermentation in the Near East around 11,000 years ago. The new Indonesian discoveries extend the timeline considerably and suggest that early foraging communities engaged with plant-based stimulants tens of thousands of years ago under Ice Age conditions.

This research sheds light on the origins of human drug use, highlighting how ancient populations may have sought and regulated psychoactive substances as part of their cultural and medicinal practices.