If you've always hated black licorice, it's OK to keep hating it—because too much of it can cause medical issues, as an elderly Canadian has found. Live Science reports on a study in the Canadian Medical Association Journal detailing the case of an 84-year-old man who turned up at the ER after a week of high blood pressure readings at home, as well as headaches, chest pain, and calf swelling. Doctors found his systolic reading to be 200mm HG; a normal reading is 120mm HG, with 180mm HG or above indicating a "hypertensive crisis." The man revealed that, for the past two weeks, he'd been throwing back a glass or two a day of homemade "erk sous," a popular Egyptian licorice tea often served during Ramadan and made from licorice root. The culprit causing the patient's distress: glycyrrhizin, a compound found in licorice root that can cause the body's potassium levels to plummet.
That, in turn, can lead to swelling, heart arrhythmia, and high blood pressure, per the FDA. Although licorice and its derivatives have long been used in Eastern medicine—as well as a sweetener in soft drinks and snacks—and the FDA has deemed them generally safe if used in moderation, "the traditional belief that licorice is a healthy natural substance without side effects drives its liberal consumption, which can occasionally be hazardous," an unrelated study notes. The FDA notes that although no one should gorge on large amounts of licorice in one sitting, many licorice-flavored products in the US don't actually have licorice in them, flavored instead with anise oil. As for the elderly patient, the study notes he went home almost two weeks later, with back-to-normal blood pressure, after "complete abstinence" from licorice while hospitalized. (A man who ate a lot of Twizzlers sued the Hershey Co.)