Indigenous communities in the western regions of South America have been using coca leaves for thousands of years for both medicinal and recreational purposes. However, the plant did not become popular throughout Europe until Western chemists developed cocaine hydrochloride in the 19th century. However, thanks to new forensic analysis, at least some people knew about (and recognized) the effects of the coca plant up to 200 years earlier than originally thought.

The evidence is detailed in a study published in Journal of Archaeological Sciences by medical and biomedical specialists from the University of Milan and the IRCCS Ca’ Granda Foundation. According to the team, at least two preserved brains buried in a crypt near a 17th-century hospital show traces of the active components of the coca plant – cocaine, benzoylecgonine and hygrine. These chemicals, particularly hygrine, indicate that the two late-Renaissance locals either chewed the leaves or drank a coca-infused tea shortly before their deaths and burial at the Ospedale Maggiore.

(Related: Sharks test positive for cocaine.)

The Ospedale Maggiore, one of Italy’s most famous hospitals, operated in Milan for almost the entire 17th century. Almost a hundred years of medical care also meant many deceased patients, which required the construction and maintenance of an ever-larger crypt near the medical facility. As the study’s authors explain, this ultimately led to an archaeological find that today contains an estimated 2.9 million bones from around 10,000 people.

The recovery and study of these remains continues to contribute to experts’ understanding of the late Renaissance and early modern period. In 2023, for example, mummified brain and bone samples were found to be positive for opium use, through the presence of Sleepy Daddy (poppy seeds) and cannabis – the latter was not yet documented at that time.

Coca was another plant that was unknown in Italy until the 19th century, when pharmacists first began to synthesize cocaine hydrochloride salts. However, after an examination of the mummified brain matter of two people buried in Ca’ Granda, this narrative must be modified somewhat.

“We present, to the best of our knowledge and belief, the first tangible evidence of the use of the coca plant in Europe. This evidence comes from archaeological examinations of human remains in the exceptional context of the crypt of Ca’ Granda. This allows us to date its use in Europe back to the 17th century,” the authors write in the conclusion of their paper.

This finding is not entirely out of the blue. As the researchers note in their study, historical written evidence shows that Spanish sailors were at least aware of the effects of the coca plant after they arrived in South America. At the same time, Europeans soon became increasingly interested in “exotic plants… in the New World” as knowledge spread across the continent. Between the 16th and 17th centuries, maritime trade expanded between South America and Milan, which was then under Spanish rule. According to the researchers, this “provides a direct link between the Italian city and the continent where the plant originated.” This “direct link” can now be traced directly to the 17th-century crypt of Ca’ Granda – although coca or cocaine is not reported in local pharmacological archives until 200 years later.

Aside from the chemical trace, the study’s authors currently don’t know much about how popular coca leaves were at the time, or whether they were used more as medicine or recreationally. However, given the burial location and method, experts believe the two bodies belonged to poorer people. With that in mind, it’s also possible that destitute, hungry residents consumed coca leaves for their appetite-stimulating side effect. If that’s true, the team suspects that coca leaves were not only present in Milan two centuries earlier than once thought – the plant may also have been cheap, popular and widely available.