In enough quantities, black licorice can kill you. Yes, the favorite sweet of grandparents everywhere must be eaten in moderation if you want to avoid the thankfully quite rare complication of being candied to death. In 2020, a 54-year-old man died following a cardiac arrest. While he was in the hospital for treatment, doctors discovered that he had low potassium levels, with no obvious cause. Following a history collected from his family, they determined he had a poor diet, as well as consuming several packets of licorice a day. About three weeks prior to his heart attack, he had switched from red licorice to black licorice, which turned out to be the cause of his problems. Black licorice contains glycyrrhizic acid, which can cause changes to potassium levels, disrupt electrolytes, and increase levels of cortisol. This can lead to hypertension, hypokalemia, metabolic alkalosis, fatal arrhythmias, and renal failure, all of which was seen in the patient. "Glycyrrhizin (also called glycyrrhizic acid) is the chemical in black licorice that gives the candy its signature flavor, but it also leads to its toxic effects," Professor of Pharmacology & Toxicology Bill Sullivan wrote in a piece for The Conversation. "Glycyrrhizin mimics the hormone aldosterone, which is made by the adrenal glands when the body needs to retain sodium and excrete potassium. Sodium and potassium work together as a kind of cellular battery that drives communication between nerves and the contraction of muscles." According to the US Food and Drug Administration (FDA), for people over 40, eating just 56 grams (2 ounces) of black licorice daily for at least two weeks could land you in the hospital with irregular heart rhythm. If you insist on eating licorice, be assured that this man's consumption was excessive, and you are extremely unlikely to eat enough to cause your own ill health. However, that's not to say it's risk-free. “Even a small amount of licorice you eat can increase your blood pressure a little bit,” Dr Neel Butala, a cardiologist at Massachusetts General Hospital told Associated Press, following the man's death. Adverse reactions are more likely in people over 40, and the length of time and volume of licorice you eat all play their part in what your reaction to black licorice will be. One 50-year-old woman saw her muscles break down after "consuming one and a half bags of black licorice bites containing 2% natural licorice during the past 3 weeks". To complicate things further, there are licorice products out there that do not contain glycyrrhizin, making them safer to eat than their authentic competitors. Check the label for ingredients, should you be planning on eating an excessive amount of licorice and want to stay safe. Source
