Popular soda brand Poppi is facing a class-action lawsuit filed by a consumer who says its products don’t improve gut health as much as their marketing suggests.

In a lawsuit filed last week in U.S. District Court in San Francisco, Kristin Cobbs said she purchased Poppi drinks on multiple occasions because of their labels, which say they are prebiotic sodas and feature the slogan, “Be Gut Happy. Be Gut Healthy.”