Ancient Tar Shows Promise, but Scientists Warn Against Big Claims

Hand holding a flaked obsidian blade — Photo: Kelsey Hurst / Shutterstock

Scientists recreated Neanderthal birch tar and found it can stop a common wound bacterium in the lab.

Story Highlights

Researchers made birch tar using Neanderthal-style methods and tested it against bacteria.
All tested tars hindered Staphylococcus aureus growth to varying degrees.
The effect was not broad spectrum and did not stop Escherichia coli in tests.
Findings suggest possible wound-care use, but do not prove medical treatment in the past.

What the new study actually did and found

Researchers produced birch tar using methods reconstructed from Neanderthal sites and time periods. They then tested each tar sample against bacteria in controlled lab dishes. Every sample hindered the growth of Staphylococcus aureus, a bacterium often found in infected wounds. The size of the “kill zone” varied by sample. Some showed moderate effects, while others were weak. Tests found no detectable effect on Escherichia coli, a different type of bacterium, showing the tar is not a cure-all.

University reports linked the results across different tar-making techniques. That matters because it reduces the chance that one lucky batch drove the finding. The team used birch species that existed in the Neanderthal era, which improves how well the lab work matches past reality. The core takeaway is simple: birch tar made like Neanderthals made it can slow or stop the growth of a key wound germ in lab tests, though strength varies by batch.

How this fits what we already know about Neanderthals

Archaeologists have long known Neanderthals made birch tar about 200,000 years ago. They used it as a sticky glue to attach stone blades to handles, which shows planning and skill. The new results add a possible bonus use. If a material they already made also slowed harmful bacteria, it may have helped with wound care. That is plausible because Staphylococcus aureus is common in skin and wound infections. But plausibility does not equal proof of treatment.

Press releases from the University of Cologne and others describe the antibacterial effect across samples and methods. They highlight that all tested tars inhibited Staphylococcus aureus growth to some degree. The journal article reports inhibition zones ranging up to about a centimeter across. Those are modest but real effects in standard lab assays. Together, the data support a focused claim: birch tar has selective antibacterial action against a wound-linked bacterium under test conditions.

Limits, next steps, and why this matters today

The study does not show Neanderthals applied tar to wounds, and it does not prove safe or effective healing on human skin. The tests measured bacterial growth in dishes, not real injuries. The effect also did not extend to Escherichia coli, so it is not broad spectrum. Future work could test more germs, check safety on skin cells, and see how storage, smoke, or dirt change performance. These steps would clarify when tar helps and when it does not.

Neanderthals may have discovered something surprising about medicine long before modern humans invented antibiotics. 🪵🧪

A substance they used to make tools could also have helped fight wound infections.

It’s called birch tar — a thick, sticky material made by heating birch…

— SSC (@ssc_globa1) October 11, 2026

The public message can drift when headlines call the tar an “ancient antibiotic.” The careful read is narrower. The science shows selective antibacterial activity in recreated birch tar and a reasonable path to explore possible wound-care roles. That thread fits a larger pattern in archaeology. We often have strong evidence for what people made and used, but weaker evidence for why. The goal now is to link chemistry, tools, and actual care practices with firmer proof.