Natural licorice, which has a very sweet taste, is extracted from the root of a shrub and used medicinally as a capsule, tablet, liquid extract, or topical gel. Most licorice candy made in the United States is artificially flavored and does not contain natural licorice.
Glycyrrhizin is the active ingredient in natural licorice. For people who are particularly sensitive to the effects of glycyrrhizin, licorice products that are specially treated to contain a much lower amount of glycyrrhizin (about one tenth of the usual amount) are available. These products are called deglycyrrhizinated licorice.
(See also Overview of Dietary Supplements.)
Claims for Licorice
People take licorice to suppress coughs, to soothe a sore throat, and to relieve stomach upset. Applied externally, it is thought to soothe skin irritation (for example, eczema). Licorice has also been claimed to help treat stomach ulcers and complications caused by hepatitis C or other liver diseases.
Evidence for Licorice
There is not enough evidence to determine whether licorice is effective for stomach ulcers or complications caused by hepatitis C or other liver diseases. Evidence does indicate that licorice in combination with other herbs relieves symptoms of indigestion and irritable bowel syndrome; however, clinical trials of both licorice alone and in combination are limited, and further evaluation is required.
Side Effects of Licorice
Licorice may increase the risk of premature delivery. Thus, pregnant women should not take licorice.
Drug Interactions with Licorice
Licorice may increase or decrease effects of estrogens.
Also, some experts believe that licorice has some activity similar to a type of antidepressant called monoamine oxidase (MAO) inhibitors and thus may intensify side effects of these medications.
Recommendations for Licorice
More Information
The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
National Institutes of Health's National Center for Complementary and Integrative Health: Licorice Root
