“Our initial hypothesis was that the synthetic gums would have a lot more microplastics because the base is a type of plastic,” Lisa Lowe, the study’s co-collaborator and a graduate student in Mohanty’s lab, explained in a statement. (Yes, certain types of synthetic gum contain petroleum-based polymers.)

Stop munching on that plastic. The U.S. National Institute of Health estimates that over 350 billion pieces of chewing gum are consumed globally every year, making gum one of the most widely enjoyed edibles on Earth.

A new study found that chewing gum releases hundreds to thousands of microplastics into saliva. Both synthetic and natural gums were found to contain microplastics, the health effects of which are not yet fully understood.