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A sacred leaf on trial: Scientists urge WHO to support decriminalizing coca

A sacred leaf on trial: Scientists urge WHO to support decriminalizing coca
Aymara women harvesting coca leaves in Bolivia. Credit: Caroline Conzelman

For thousands of years, people in the Andes have chewed the leaves of the coca plant to stave off hunger, treat altitude sickness, and sustain energy. Yet under international law, this ancient crop is treated as harshly as cocaine and fentanyl. Now, scientists say it's time to end that contradiction.

A new published in Science argues that clearly supports the coca leaf as a benign, useful, and culturally paramount crop plant that should be removed from the list of Schedule I substances—where it currently appears alongside cocaine and fentanyl—under the 1961 "Single Convention on Narcotic Drugs."

"Coca's record of safe use and cultural importance stands in stark contrast to the harms of purified cocaine," said lead author Dawson M. White, Postdoctoral Researcher in the Department of Organismic and Evolutionary Biology at Harvard.

"Recognizing this difference is essential for evidence-based policy and for aligning with the goals expressed by South American communities most affected by prohibition."

The analysis arrives at a pivotal moment, as the World Health Organization (WHO) is currently reviewing the legal status of coca. An expert report compiled by the WHO confirms both the lack of harm from the coca leaf and the tangible harms caused by its prohibition. The WHO's will meet in Geneva from October 20–22, 2025, to formalize a recommendation to the United Nations (UN) Commission on Narcotic Drugs.

"This meeting is a rare opportunity for the WHO and UN to correct a classification rooted in colonial bias and outdated science," said White.

The authors draw on evidence from anthropology, evolutionary biology, biochemistry, pharmacology, economics, and the social sciences to distinguish the coca plant from its purified alkaloid, cocaine.

The findings also point to the need for long-overdue reform of global drug policy, highlighting that coca has been cultivated for more than 8,000 years and safely used as a mild stimulant, medicine, and ritual element across more than 100 cultures.

A sacred leaf on trial: Scientists urge WHO to support decriminalizing coca
Amazonian coca leaf. Credit: Khoka Project

The research also references a coordinated from coca producer and consumer communities supporting petitions by Bolivia and Colombia.

The document—signed by traditional coca producers, Indigenous representatives, and allied organizations—urges the WHO to recognize coca's cultural, medicinal, nutritional, and social value; to reject its stigmatization based on cocaine use; and to recommend its removal from international control lists.

"Efforts to reform coca policy must begin with the people who know the plant best," said Claude Guislain of the Indigenous Medicine Conservation Fund.

"Indigenous peoples cultivate sophisticated knowledge systems that have used coca to sustain balance within their communities and territories for millennia. Our role has been to walk alongside them—to amplify their voices and help ensure that international policy reflects the realities they live and defend."

"The coca leaf is not a narcotic, but a sacred and nutritious plant with deep cultural roots," said Ricardo Soberón Garrido, former President of DEVIDA, Peru's National Commission for Development and Life Without Drugs, which coordinates the country's drug policy and coca-development strategies. "De-scheduling coca would uphold Indigenous rights and align global policy with modern science."

In addition, the paper reviews findings from the WHO's "Critical Review Report on Coca Leaf " (2025), which concludes that traditional uses pose no significant public-health risks.

The study finds that removing coca from the list of controlled substances would correct a long-standing scientific and legal misclassification. "Such a change would recognize the rights of Indigenous and other coca-growing communities while allowing for evidence-based regulation informed by traditional knowledge," said White.

The authors also note that de-scheduling coca could enable on its diverse bioactive compounds and create new, sustainable economic opportunities in rural regions. They emphasize that the ongoing WHO review offers a rare and timely chance to align international drug policy with science, justice, and cultural reality —allowing the global community to understand and benefit from the coca plant responsibly.

Many of the co-authors first met at the "Wisdom of the Leaf" summit in Urubamba, Peru, hosted by the McKenna Academy of Natural Philosophy, which released a from that meeting.

More information: Dawson M. White et al, Scientific distinctions between coca and cocaine support policy reform, Science (2025). .

Journal information: Science

Provided by Harvard University

Citation: A sacred leaf on trial: Scientists urge WHO to support decriminalizing coca (2025, October 15) retrieved 15 October 2025 from /news/2025-10-sacred-leaf-trial-scientists-urge.html
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