While we don’t often think of food as having the potential to prove lethal in large doses, in rare cases it’s certainly possible. Case in point: According to the Associated Press, a 54-year-old man in Massachusetts died last year after consuming an excessive amount of black licorice candy, which is a popular Halloween treat.

In the case, which was recently published in the New England Journal of Medicine, the unnamed man passed away as a result of his heart stopping. The event is believed to have been brought on by his regular and excessive intake of black licorice, which contains glycyrrhizic acid, also known as glycyrrhizin, a sweetening compound found in the licorice root which can cause high blood pressure, heart rhythm irregularities, and potassium and electrolyte imbalances when ingested in large quantities.

The man reportedly ate a bag and a half of black licorice daily for several weeks before collapsing. Doctors determined he suffered from low potassium, which created irregular heart rhythms.

The case has brought more attention to the dangers of glycyrrhizic acid, which the Food and Drug Administration warns can be harmful in amounts found in as little as 2 ounces of black licorice per day when eaten consistently over a two-week period. The compound is also found in jelly beans, licorice teas, and other food. Those with existing heart conditions should take particular care not to overindulge.

[h/t Associated Press]