Toxicology traces psychoactive substances in Inca mountain sacrifice mummies

Chemicals embedded in hair and nail keratin from people sacrificed at Inca mountain shrines have been read through toxicological analysis, identifying psychoactive substances consumed before death, according to work published in 2026 in the journal Antiquity and summarized by the University of Cambridge.

Capacocha ranked among the empire’s most sacred ceremonies: children and young women were killed in veneration of major deities and treated as intermediaries between the living and the divine. Participants were often given psychoactive plants, possibly in the belief that the drugs would heighten prophetic power. Historical texts already record Inca use of such plants, yet the specific mixtures tied to capacocha have remained poorly known. Andean figurines with cheek bulges have been read as images of coca chewing in that setting, while the bodies themselves preserve the compounds in keratin that modern toxicology can recover.

Dr. Dagmara Socha of the University of Warsaw, the study’s lead author, told the Cambridge release that earlier analyses either produced negative results or focused primarily on coca leaves. Recent toxicology, she said, can detect the same compounds at low concentration. Socha’s stated aim was to identify a broader range of psychoactive substances given to the children and to test whether patterns of use would clarify how capacocha was staged at different shrines. The team examined hair and nail samples from eight mummies recovered on mountains in Peru and Argentina, spanning a wide set of sacrificial practices across the empire.

In every mummy in that group they identified cocaine, which the researchers link to chewing coca leaves. Coca served as offerings to the gods and may also have eased altitude sickness and fatigue on the climbs. In four of the eight mummies they also found evidence of alcohol, read as possible corn beer, or chicha, which historical accounts say was used to dull the senses in the ritual’s final stage. In the mummy known as the Lady of Ampato, or Juanita, the same work detected harmine, an alkaloid linked to Banisteriopsis plants used in ayahuasca preparations. Socha has suggested that a harmine-bearing drink may have held a particular role in rites tied to that mountain.

Taken together, the eight-mummy series shows clear differences in what each person received, which the authors read as local adaptation of capacocha to distinct cults and sacred places rather than a single fixed script. A shared drug sequence at other capacocha shrines would weaken that local-adaptation reading. The pattern is drawn from the eight mummies examined in that Antiquity study.