Ancient Chewing Gum That Holds the DNA Secrets of Its Maker

If you’ve ever chewed gum to pass the time, calm your nerves, or just out of habit, you’re in good company. Humans have been doing something similar for thousands of years. In fact, one of the most extraordinary archaeological discoveries of the past decade started with what looks like nothing more than an old lump of chewed gum.

In 2018, researchers working on the Danish island of Lolland unearthed a small, dark piece of birch pitch at the Syltholm site. It dates back nearly 6,000 years to the Mesolithic era. Within its hardened layers, scientists extracted a complete human genome. This included the DNA of the woman who chewed it. The genome also contained traces of her diet, her health, and even the bacteria that once lived in her mouth.

It’s essentially the world’s oldest piece of “chewing gum.” It has given us one of the most vivid windows into the life of a single person who lived thousands of years ago.

What Exactly Is Birch Pitch?

Birch pitch, or birch tar, is made by heating birch bark until it breaks down into a sticky, tar-like substance. For early humans, it worked as a strong glue for attaching stone blades to wooden handles. It was also used for repairing cracked pottery and binding weapons together. But the story doesn’t end there—archaeologists quickly realized some pieces of birch pitch had clear tooth marks on them.

Why were people chewing it? The most likely reason is practical: chewing softened the resin, making it easier to mold and use as adhesive. But there may have been other motives too. Birch pitch contains natural antiseptic compounds, which could have helped soothe toothaches or fight off infection.

The Discovery at Syltholm

The lump of chewed birch pitch was found at Syltholm, a site that archaeologists describe as a “time capsule” of Mesolithic life. The area was once a coastal lagoon. It was later covered by layers of mud, which helped preserve organic materials in extraordinary detail. Thus, even something as fragile as ancient spit and bite marks survived for nearly 6,000 years.

From this one small piece, scientists extracted not just traces of human saliva but an entire genome. It was the first time such a complete set of genetic information had been recovered from anything other than human remains. Suddenly, we weren’t just looking at an object from the past. We were meeting a person.

Who Was the Chewer?

The DNA revealed that the gum had been chewed by a young woman. She is now nicknamed “Lola” after the island of Lolland. And she wasn’t quite what we might have pictured. According to her genetic profile, she likely had dark skin, dark hair, and striking blue eyes.

Her DNA also contained details about her lifestyle. Traces of hazelnut and duck proteins were found. This suggests these foods had recently been part of her diet—something she may have eaten hours or even minutes before chewing the birch pitch. In addition, scientists detected remnants of the Epstein-Barr virus, which still infects people today and is linked to mononucleosis.

Perhaps most fascinating was the preservation of her oral microbiome: the community of bacteria that lived in her mouth. This snapshot gives researchers a rare look at the health, hygiene, and diet of people in the Mesolithic era.

Until recently, most ancient DNA research relied on bones or teeth, which are rare, fragile, and don’t always survive. Birch pitch opens a whole new category of material for DNA preservation. It means we could potentially learn about countless individuals from the past, even in places where no human remains exist.