Hair analysis reveals ancient drug use

A 3,000-year-old tangle of hair found in a cliff-side burial cave on Menorca, an island in the Mediterranean Sea, contains chemical residues of multiple psychoactive plants, reports a new study (Sci. Rep. 2023, DOI: 10.1038/s41598-023-31064-2 ). The results offer the earliest direct evidence of consumption of psychoactive substances in Europe.

The cave, called Es Càrritx, was used as a burial site between about 1450 and 800 BCE, and its funerary contents were first discovered by cave scientists in 1995. Archaeologists discovered at least 210 deceased individuals in the cave and found that at least a few of them underwent a special ritual in which strands of their hair were dyed red, cut off, and placed in small tubes made of horn and wood. Researchers found 10 such tubes of hair, says Elisa Guerra-Doce, an anthropologist at the University of Valladolid in Spain who led the study, adding that it’s unknown how many individuals’ hair each tube contains.

To explore whether people in this Bronze Age community used psychoactive compounds, the researchers used ultra-high-performance liquid chromatography–high-resolution mass spectrometry (UHPLC-HRMS) to analyze hair from one of these tubes. They detected alkaloids present in atropine, scopolamine and ephedrine. Each psychoactive substance was found in multiple plants that grew on the island. Based on the ratio of scopolamine to atropine in the hair, the team reasoned that the deceased had consumed a plant called Datura stramonium, which causes delirium and out-of-body experiences. They traced the ephedrine, which causes excitement and enhanced mental alertness, to Ephedra fragilis.

The longest hairs in the tubes were about 13 cm long, suggesting that the drugs that got incorporated into them were not part of the burial ceremony but were likely consumed at least a year before death, says Guerra-Doce. Analyzing hair samples from other tubes might help reveal how widely used these substances were, she says.