Most versions of black licorice contain glycyrrhizin, a sweetening compound found in the licorice root. While tasty, glycyrrhizin can affect potassium levels in the body, causing them to fall to dangerously low levels. High blood pressure, swelling, and even heart issues can develop as a result.

It’s not just bingeing that can cause issues. According to the Food and Drug Administration, adults over 40 who eat more than two ounces of black licorice a day for two weeks could suffer heart problems like arrhythmia. If you have a history of heart disease, you’re even more susceptible to complications.

The FDA recommends using a little common sense when consuming black licorice, eating it in moderate amounts and stopping if you notice any adverse symptoms. If you do experience potassium level drops, it’s usually reversible once you put the bag down. Treats that are licorice-flavored are typically artificial and won’t have the same effect as the actual plant root—but for your waistline’s sake, try to avoid gorging on anything.