DUBAI, United Arab Emirates (CNN) — Scientists have found direct evidence that people in Bronze Age Europe used hallucinogenic drugs, possibly as part of an ancient ritual.

Traces of plant-based alkaloids, which affect cognition and cause trance and euphoria, are found in strands of human hair dating back nearly 3,000 years.

Researchers discovered locks of hair along with other burial items in a burial site at Es Càrritx in Menorca, one of the Balearic islands off Spain’s east coast in the Mediterranean Sea.

Chemical analysis revealed the presence of ephedrine in the hair fibers, as well as atropine and scopolamine, psychotropic substances that cause confusion, emotional disturbance and severe hallucinations, the researchers reported Thursday in the journal Scientific Reports.

Drug use among humans has been a known practice for thousands of years based on evidence previously found in Eurasia and the Americas.

But in Europe, the presence of hallucinogenic plants at historic sites has given archaeologists an incomplete picture.

Elisa Guerra-Dossi, an associate professor in the history department at the University of Valladolid in Spain, told CNN that scientists do not yet have evidence that people in the community actually consumed the plants.

With these new findings, “we provide the oldest evidence of drug consumption in European prehistoric times,” Ducey said.

The cave “Es Càrritx” was discovered in 1995, its entrance is located about 25 meters from the top of a cliff, and it has seven chambers.

The cave served as a funerary site from 1400 AD to 800 BC, and more than two hundred adults and children, male and female, were buried.

But some bodies received special treatment, and after being brought to the cave, locks of hair were dyed red, carefully combed, cut, and then placed inside closed tubes made of horns or wood.

In other burials where these rituals were performed, pipes were placed near the bodies.

But in the Es Càrritx cave, 10 of these pipes, along with other funerary items, were hidden in another chamber, the study authors said.

The locks of hair in the tubes were red in color and 13 centimeters long.

The researchers analyzed the fibers by chemically separating the components in the hair, then identifying the molecules according to the mass of their ions.

All the compounds discovered came from plants that grow in Menorca, such as devil’s snare (Datura stromonium), white bengii (Hysiamus albus) and mandrake (Mandragora autumnalis).

The visions caused by taking scopolamine and atropine are “violent and unpleasant,” says Dagmara Socha, a researcher at the Center for Andean Studies at the University of Warsaw in Poland.

Socha, who was not involved in the study, is investigating the ancient use of hallucinogenic compounds.

Pipes found in the Es Càrritx cave, containing tufts of hair, were found untouched in a sealed chamber from 800 BC, making it unlikely that the compounds were due to recent contamination at the site.

Instead, the hair absorbs the chemicals after they are ingested.

Based on the analyses, drug use continued for a year prior to death.

The discoveries of the Es Càrritx cave may also shed light on how drug use determined certain roles in prehistoric European societies.