Scientists have discovered the earliest evidence of drug use in teeth belonging to a hunter-gatherer who lived in Indonesia 16,000 to 25,000 years ago. Researchers found deep grooves on the molars, likely caused by incessant sucking on betel nuts, which release psychoactive stimulants. This discovery pushes back the timeline of human pharmacological experimentation by 3,000 to 12,000 years, predating the previous oldest evidence of beer brewed in Israel 13,000 years ago.

The teeth were found in a cave on the island of Sulawesi. Researchers identified traces of arecoline, the psychoactive ingredient in betel nut, on the ancient dental remains. The matching dental-wear patterns on a second forager who lived 7,000 years ago suggest this behavior was passed down over many millennia in the region.

Scientists speculate the ancient humans used the nuts as painkillers, though the practice wore teeth down to the pulp, potentially creating a cycle of addiction. Piyawit Moonkham, an anthropological archaeologist at Chiang Mai University in Thailand, called this the oldest evidence of human drug use. The study was published in the journal Science Advances.