A 54-year-old man died after eating a bag and a half of liquorice every day, according to doctors.
The construction worker, who had shown no symptoms, suddenly had a heart attack while out eating in a fast food restaurant, according to a report in the New England Journal of Medicine.
Doctors say glycyrrhizic acid in liquorice triggered the extreme reaction.
Dr Elazer R Edelman said studies had shown glycyrrhizic acid - found in liquorice - could cause "hypertension, hypokalemia, metabolic alkalosis, fatal arrhythmias, and renal failure".
The symptoms were all later found in the patient including hypokalemia - where potassium levels in blood become dangerously low.
Weeks before his death the man had switched from eating red liquorice to black.
Dr Andrew L Lundquist concurred in the report that the liquorice was to blame for the man's death.
He wrote: "Further investigation revealed a recent change to a liquorice-containing candy as the likely cause of his hypokalemia."
