Microplastics—tiny plastic bits that can take hundreds of years to break down—are everywhere, from tap water to tea bags, leaving traces in our blood and lungs. Now you can add your favorite chewing gum to the list, thanks to the alarming findings of a new study.

Chewing gum, whether natural or synthetic, contains plant-based or synthetic plastic polymers to enhance texture and flavor retention, making it a source of microplastics, explained the pilot study, which was presented at the spring meeting of the American Chemical Society in San Diego. And those microplastics can be ingested through saliva—with 94% released within the first eight minutes of chewing, they found.

“Our goal is not to alarm anybody,” Sanjay Mohanty, the project’s principal investigator and an engineering professor at the University of California, Los Angeles (UCLA), said in a news release. “Scientists don’t know if microplastics are unsafe to us or not. There are no human trials. But we know we are exposed to plastics in everyday life, and that’s what we wanted to examine here.”

How dangerous are microplastics?

Recent studies into microplastics suggest they are making their way into our bloodstreams. And while the science is still evolving, Heather Leslie, an independent scientist who pioneered microplastics and human health research in Europe, previously told Fortune, “The evidence for inflammatory effects and metabolic changes in tissues where microplastics accumulate is building.”

A recent report published in Nature Medicine showed that microplastics have been found present in multiple human organs, including the blood, lungs, placenta, and feces, as well as in breast milk, testes, and semen. That ingredients of the plastics found present have already been linked to heart attack and strokes, inflammatory bowel disease, infertility, cancers, and neurodevelopmental disorders.

What did the study show about chewing gum?、

The study, which was small, looked at the release of microplastics during consumption by having a human subject chew 10 different types of both natural and synthetic (the latter being what most mainstream brands are) for two to 20 minutes each. (Researchers would not reveal the specific types of gum in order to not unfairly cause them bad publicity, but told Fortune, “We used top 10 brands one can find in a supermarket.”)

Chewing gums are made from a rubbery base, sweetener, flavorings, and other ingredients. Natural gum products use a plant-based polymer, such as chicle or other tree sap, to achieve the right chewiness, while other products use synthetic rubber bases from petroleum-based polymers.

“Interestingly,” the researchers noted, “synthetic gums released a similar amount of microplastics as natural, plant-based gums.” Four main plastic polymers were detected in the saliva, with polyolefins being the most common. These findings suggest that chewing gum may lead to the direct ingestion of microplastics, potentially posing health risks.

Saliva was then collected and analyzed for microplastics, and the results revealed that each gram of gum can release up to 637 microplastic particles, with almost all released within eight minutes. For that reason, Lowe suggests that if people want to reduce their potential exposure to microplastics from gum, they should chew one piece longer instead of popping in a new one.

Because the study was limited to identifying microplastics 20 micrometers wide or larger because of the instruments and techniques used, it’s likely, Mohanty says, that smaller plastic particles were not detected in saliva. Next, he and lead author Lisa Lowe plan to assess the potential release of smaller, or nano-size, plastics from chewing gum, which can get into the bloodstream.

“The plastic released into saliva,” Mohanty concludes, “is a small fraction of the plastic that’s in the gum.”