There's a warning about many people's least favorite candy, warning that too much black licorice can cause abnormal heart rhythms, as well as high blood pressure, edema (swelling), lethargy and congestive heart failure.
Black licorice is so strongly flavored that it’s widely yucked, but not everybody hates it. In fact, apparently some people eat so much they have serious health issues.
How much is too much? According to the FDA, two ounces a day for two weeks straight, and it has to be the real stuff, not this fake anise-oil flavored licorice that you might find in some plastic pumpkins tomorrow.
The FDA specifies that this warning predominately applies to licorice-lovers older than 40. It turns out that black licorice contains the compound glycyrrhizin, which is the sweetening compound derived from licorice root, and glycyrrhizin can cause potassium levels in the body to fall.
From the FDA:
Licorice, or liquorice, is a low-growing shrub mostly grown for commercial use in Greece, Turkey, and Asia. The National Institutes of Health (NIH) says the plant's root has a long history of use as a folk or traditional remedy in both Eastern and Western medicine. It has been used as a treatment for heartburn, stomach ulcers, bronchitis, sore throat, cough and some infections caused by viruses, such as hepatitis; however, NIH says there are insufficient data available to determine if licorice is effective in treating any medical condition.
Licorice is also used as a flavoring in food. Many "licorice" or "licorice flavor" products manufactured in the United States do not contain any licorice. Instead, they contain anise oil, which has the same smell and taste. Licorice root that is sold as a dietary supplement can be found with the glycyrrhizin removed, resulting in a product known as deglycyrrhizinated licorice, or DGL, NIH says.
The agency went on to recommend the following “if you have a fondness for black licorice”:
No matter what your age, don't eat large amounts of black licorice at one time.
If you have been eating a lot of black licorice and have an irregular heart rhythm or muscle weakness, stop eating it immediately and contact your health care provider.
Black licorice can interact with some medications, herbs and dietary supplements. Consult a health care professional if you have questions about possible interactions with a drug or supplement you take.
If you've experienced any problems after eating licorice, contact the FDA consumer complaint coordinator in your area.