Q & A: Craving licorice

by Jackie Hart, MD

Q: I have cravings for licorice on a daily basis. Is it true that eating licorice aggravates high blood pressure?

A: Licorice (Glycyrrhiza glabra) is a plant that grows wild in parts of Europe and Asia. One of the active components of licorice, glycyrrhizin, gives real licorice candy its sweet taste. As a medicinal herb, the root of the licorice plant has been used to treat ulcers, arthritis, cough, and infections such as the common cold or bronchitis.

Unfortunately, though, licorice root can be quite toxic. When large amounts of licorice root are ingested over an extended period of time, it can lead to high blood pressure, headache, lethargy, and loss of potassium in the urine that can lead to irregular heart rhythm and extreme weakness. To give you some sense of how much licorice it takes, in one experiment volunteers ate 100 to 200 grams of licorice twists (10 to 20 pieces) every day; after one month the participants began to experience the negative side effects described. A man who ate 700 grams (70 pieces of the twists) of licorice in nine days required a four-day hospitalization.

Licorice is found in some unexpected places. Tobacco products, for example, including cigarettes, cigars, pipes, and chewing tobacco all contain licorice; commercial cough syrups and cough drops also contain licorice. Some herbal cough syrups contain as much as 0.5 grams of licorice per serving.

For medicinal purposes today, licorice can be processed to remove the glychyrrhizin the component responsible for the negative side effects. The result is called deglycyrrhizinated licorice or DGL.

The licorice that you crave, though, may actually be anise flavoring found in "licorice" candy often sold in the United States. Unlike the authentic licorice candy sold in Europe, what tastes like licorice in America may actually be anise oil. Also unlike genuine licorice, anise does not cause the same negative side effects, including high blood pressure. Therefore, with American "licorice" candy, you can have the great taste without the harmful results.