Man Died After Eating a Bag of Black Licorice Every Day

Doctors at Massachusetts General Hospital said the unusual case highlighted the risk of consuming too much glycyrrhizic acid, which is found in black licorice.

The black and chewy candy contains glycyrrhizic acid, a plant extract that can lead to high blood pressure if consumed in large doses.

He had no history of heart problems. He walked his dog regularly and worked a physically demanding job as a construction worker, according to his doctors.

Then, in January 2019, he collapsed at a McDonald’s and died.

The likely culprit? Black licorice, according to the doctors who treated him and who this week published their findings about the unusual case in The New England Journal of Medicine.

The report said the man, an unidentified 54-year-old from Massachusetts, had consumed one to two large bags of black licorice a day for three weeks. That habit caused his potassium levels to drop precipitously, prompting a cardiac arrest, according to the study. He never regained consciousness after his collapse and died about 24 hours after he arrived at Massachusetts General Hospital.

Aspiring doctors are taught in medical school that black licorice contains glycyrrhizic acid, a plant extract that is often used as a sweetener in candies and other foods and can lead to dangerously low potassium levels if it is consumed in high enough doses.

The man in Massachusetts had a poor diet and smoked a pack of cigarettes a day, according to his friends and family, his doctors said. But it was a switch from red to black licorice three weeks before his death that doctors said proved fatal.

Dr. Henson said she interviewed the man’s friends and family members, and doctors ran multiple laboratory tests that confirmed the man’s potassium levels were well below normal.

They studied his medical history, which included heroin use, though he had not used opiates for three years. There was no family history of cardiac disease or other conditions that would have led to low potassium levels, said Dr. Henson, who is now a fellow at Duke University School of Medicine in Durham, N.C.

“We had no other clear cause for why his potassium levels were so low,” she said.

Dr. Henson said people who like to eat the occasional piece of licorice should not be alarmed by the case in Massachusetts.

Black licorice is not a poison, she said.

“It’s fine taken in sort of small amounts, infrequently,” Dr. Henson said. “But when taken on a regular basis, it can lead to these issues.”