Hair and nails of Inca mummies reveal varied drug use in capacocha rites

Toxicological analysis of hair and nails from eight Inca mummies has shown that the children and young people sacrificed in the capacocha ritual did not all receive the same substances. Coca use was universal in the sample, but alcohol appeared in only some individuals, and one body carried a marker linked to an ayahuasca-type plant. The study, led by Dr Dagmara Socha of the University of Warsaw, is published in the journal Antiquity.

A ritual known mainly from texts

The capacocha was among the most sacred ceremonies of the Inca Empire. Children and young women were offered to important deities and came to be regarded as intermediaries between the living and the divine. Historical accounts record that the Incas used psychoactive plants, and the sacrificial victims may have been given such substances to heighten their perceived prophetic powers. Yet direct evidence of what they consumed has been scarce. According to Socha, earlier chemical analyses either found nothing or concentrated mainly on coca.

Mummified remains offer a way round this problem. Compounds taken into the body become incorporated into keratin-rich tissues such as hair and nails, where they can persist and later be detected. Socha notes that recent improvements in toxicology make it possible to identify very low concentrations of such compounds.

What the samples showed

The team analysed hair and nail samples from eight mummies recovered from several mountains in Peru and Argentina, chosen to represent a broad range of sacrificial practice across the empire. The main results were:

• Cocaine in every individual, indicating that all of them had chewed coca leaves. Coca was a religious offering, but it may also have eased altitude sickness and fatigue on the long climbs to the shrines.
• Alcohol in four individuals, possibly from chicha, a maize beer. Historical sources describe it being given to the children to dull their senses and keep them calm in the final stage of the ritual.
• Harmine in one individual, the mummy known as the Lady of Ampato, or Juanita.

The harmine finding

Harmine is an alkaloid associated with plants of the genus Banisteriopsis, which are a principal ingredient of the ayahuasca drink. Socha describes its presence in Juanita as one of the most intriguing results and suggests that a harmine-containing beverage may have had a particular role in ceremonies tied to Mount Ampato. The detection shows that a substance beyond coca and maize beer was involved in at least one case, although the analysis cannot by itself reveal how the drink was prepared or what it meant to participants.

Implications and limits

The authors conclude that the capacocha was not a uniform rite. Differences between individuals point to adaptation to local religious traditions and to the particular deities or sacred places concerned. This fits a picture of an empire that incorporated regional cults into a shared ceremonial framework rather than imposing a single script.

The sample is small, with eight individuals across a very large geographical range, so the patterns are suggestive rather than definitive. A substance absent from a sample does not prove it was never given, since detectability depends on dose, timing and preservation. Wider sampling of other capacocha burials, and comparison with the archaeological context of each shrine, would help test whether the differences follow particular mountains or cults. The work also shows the value of applying more sensitive analytical methods to well-studied human remains, which can still yield new information about practices that written sources describe only in outline.

Source: Analysis of Inca mummies identifies the drugs used in their most important sacrificial ritual (Phys.org, 3 November 2026).

Image: AI-generated illustration.