FRIDAY, Oct. 28, 2022 (American Heart Association News) — “How do you feel about black licorice?” sounds like a question to start a simple chat at a Halloween party – or a silly internet fight. It’s a love-it-or-hate-it candy that evokes strong opinions.

But if you ask a health expert, expect a tough talk — because eating large amounts of black licorice can cause complications that are “acutely life-threatening,” said Dr. Christopher Newton-Che, a cardiologist at Massachusetts General Hospital and Harvard Medical School in Boston.

No one is saying that a twist or two now and then is a problem. But before you get into that, you want to learn about the dangers of over-enthusiasm.

The root of the problem is the real root. Licorice, or Glycyrrhiza glabra, is a type of legume (such as peas or beans) found in southern Europe, the Middle East, and Asia. The root of the licorice plant has been used since ancient times. Soldiers used licorice root extract to quench their thirst in battle and on long marches. And large sums were found buried in Tutankhamun’s tomb. Depending on your sensibilities, this makes black licorice the most royal of treats, or something cursed that no mortal can be bothered with.

Licorice root provides a tangy sweetness that black licorice lovers love and others hate. You won’t find it in red licorice, and some black licorice candies use artificial flavors or anise oil, which has a similar flavor. But some of the most famous black licorice candies use natural licorice extract, which is also found in some teas, beers, and other products.

The traditional taste of black licorice comes from a chemical called glycyrrhizin, which is 50 times sweeter than cane sugar. “It’s a pretty strong smell,” Newton-Che said. And it can do much more than add flavor.

Consuming large amounts of black licorice can significantly lower potassium levels in the body. Potassium is important for heart health, and if its levels drop dramatically, it can lead to problems like irregular heart rhythms and congestive heart failure.

Or worse.

In 2019, Newton-Cheh helped treat a man who went into cardiac arrest after his potassium levels dropped to less than half of normal.

According to a case report published in the New England Journal of Medicine, his health problems included poor nutrition and smoking. His family said he had a habit of eating a bag or two of red licorice every day. But three weeks ago it switched to black.

He died, Newton-Che said, of a traumatic brain injury caused by first responders having difficulty getting his heart back into a normal rhythm — a problem Newton-Che said may have been related to the low potassium

Even if the results aren’t as immediate and drastic, glycyrrhizin can lead to long-term heart problems by causing the body to retain sodium. “So patients will have higher blood pressure as a consequence,” Newton-Che said.

Licorice is usually not fatal, but serious reactions are hardly unusual. Black licorice has also been linked to other problems. A 2009 study of women in Finland linked high consumption during pregnancy to poorer cognitive abilities in their children later. And the Food and Drug Administration warns that black licorice may interfere with some medications, herbs, and dietary supplements. The American Heart Association says this includes some diuretics and heart failure medications, so Newton-Che said people should check with their doctor about possible interactions.

But there’s no good answer to the question of how safe black licorice is, he said. – It is poorly studied.

The FDA “encourages moderation,” while warning, “If you’re 40 or older, eating 2 ounces of black licorice a day for at least two weeks could put you in the hospital with an irregular heart rhythm.”

If you’ve eaten a lot of black licorice and you have an irregular heart rhythm or muscle weakness, stop eating it immediately and consult a health care professional, the FDA says.

In addition to candies, black licorice in various forms is often promoted as a dietary supplement. Newton-Che said most claims of possible benefits have not been thoroughly studied. “It’s very difficult to sort out the unproven theories that exist in the alternative medicine field about the potential health benefits of licorice,” he said, so anyone taking it should check with their doctor.

So what does that leave licorice fans?

“I would say artificially flavored black licorice and red licorice are not equally dangerous,” Newton-Che said. This does not make them healthy; they still contain sugar, which can lead to obesity and other health problems if you consume too much. Ingredients vary by brand, but one widely available package contains 140 calories and 17 grams of sugar per 40-gram serving. (That’s just under 1 1/2 ounces.) The AHA recommends limiting added sugars to no more than 6% of calories per day — about 100 calories per day for women and 150 for men.

Newton-Cech said the appearance of a few pieces of black licorice in a child’s well is not a cause for concern. But in general, limiting the total amount of candy a child eats is a healthy idea, he said.

Newton-Che himself does not shy away from black licorice. But he probably won’t be raiding his kids’ stash on Halloween, either, for a reason that’s more subjective than scientific: “I don’t particularly like the taste.”

American Heart Association News covers heart and brain health. Not all views expressed in this story reflect the official position of the American Heart Association. Copyright owned or owned by the American Heart Association, Inc. and all rights reserved. If you have questions or comments about this story, please write

Michael Merschel, American Heart Association News