BlissTree | Halloween Buzzkill: Black Licorice Overdose Could Cause Heart Failure, Says FDA BlissTree Or, more likely: Increase your risk of hypertension, heart swelling and lethargy, and at worst, congestive heart failure. Apparently, the problem is glycyrrhizin—a chemical compound found in licorice root that tastes sweet and may trigger a drop in ... Black Licorice Can Cause Heart Failure Black Licorice: Dangerous Candy Halloween Health Scare: Beware Black Licorice Overdose |