5,000-Year-Old Evidence of Charcoal-Based Medicine and Ancient Antibiotic Resistance Unearthed in Zonguldak’s İnönü Cave

A groundbreaking interdisciplinary study led by archaeologists and microbiologists from Zonguldak Bülent Ecevit University (BEUN) has revealed that prehistoric communities in northern Türkiye were using charcoal for medicinal purposes 5,000 years ago. The same project also traced the origins of antibiotic resistance genes back more than 6,000 years, challenging assumptions that resistance emerged solely due to modern drug use.

Ancient Healing Practices from the Early Bronze Age

Excavations at İnönü Cave in Karadeniz Ereğli, ongoing since 2017 under the direction of Associate Professor Hamza Ekmen, have yielded remarkable insights into prehistoric health practices. Soil samples analyzed from five stratigraphic layers revealed that Early Bronze Age inhabitants treated gastrointestinal illnesses—such as nausea, vomiting, and abdominal pain—with charcoal-based substances.

Associate Professor Fadile Gülden Ekmen of BEUN’s Archaeology Department emphasized the cultural significance of the discovery:

“The narrative of coal use in Zonguldak typically begins in the 19th century with Uzun Mehmet’s discovery, but this evidence shows that charcoal derivatives were already used for healing purposes 5,000 years ago. This demonstrates not only deep knowledge of local resources but also a cultural continuity of medicinal practices that persists today through activated charcoal treatments.”

Antibiotic Resistance: A 6,000-Year Legacy

Microbiological analyses, conducted by Associate Professor Şükran Öztürk from BEUN’s Faculty of Pharmacy in collaboration with Professor Emre Keskin and his team from Ankara University, identified antibiotic resistance genes in three of the cave’s stratigraphic layers. These findings prove that antibiotic resistance is an ancient phenomenon shaped by environmental and ecological factors rather than exclusively by modern drug overuse.

“Our results show that resistance genes have existed for millennia, influenced by microbial communities, climate conditions, and human activity,” Öztürk noted. “This calls for a holistic ‘One Health’ approach to modern healthcare, recognizing that antibiotic resistance is a deeply rooted natural process.”

Redefining the Medical History of Anatolia

The İnönü Cave project, supported by Türkiye’s Ministry of Culture and Tourism, represents a rare fusion of archaeology and microbiology, offering a detailed snapshot of prehistoric life in Anatolia. Alongside mapping microbial diversity, researchers reconstructed the health challenges of ancient communities, demonstrating that many medical practices once thought modern have their roots in deep prehistory.

This discovery not only reshapes the medical history of Zonguldak, a city synonymous with industrial coal mining, but also highlights how prehistoric knowledge of natural resources laid the foundations for therapeutic practices still used in modern medicine.

Öztürk S, Ekmen F, Ekmen H, Ünal EM, Er A, Keskin E, et al. (2025). Decoding past microbial life and antibiotic resistance in İnönü Cave’s archaeological soil. PLOS ONE 20(7): e0326358. https://doi.org/10.1371/journal.pone.0326358

Cover Image Credit: Soil DNA analysis from Türkiye’s İnönü Cave reveals 5,000-year-old charcoal therapy and ancient antibiotic resistance genes. Credit: Öztürk et al., 2025, PLOS ONE