This fact sheet provides basic information about licorice root--common names, uses, potential side effects, and resources for more information. Most licorice is grown in Greece, Turkey, and Asia. Licorice contains a compound called glycyrrhizin (or glycyrrhizic acid).

Common Names--licorice root, licorice, liquorice, sweet root, gan zao (Chinese licorice)

Latin Name--Glycyrrhiza glabra, Glycyrrhiza uralensis (Chinese licorice)

What It Is Used For

Licorice root has been used as a dietary supplement for stomach ulcers, bronchitis, and sore throat, as well as infections caused by viruses, such as hepatitis.

How It Is Used

• Peeled licorice root is available in dried and powdered forms.
• Licorice root is available as capsules, tablets, and liquid extracts.
• Licorice can be found with glycyrrhizin removed; the product is called DGL (for "deglycyrrhizinated licorice").

 What the Science Says

• A review of several clinical trials found that glycyrrhizin might reduce complications from hepatitis C in some patients. However, there is not enough evidence to confirm that glycyrrhizin has this effect.
• There are not enough reliable data to determine whether licorice is effective for stomach ulcers.

Side Effects and Cautions

• In large amounts, licorice containing glycyrrhizin can cause high blood pressure, salt and water retention, and low potassium levels, which could lead to heart problems. DGL products are thought to cause fewer side effects.
• The safety of using licorice as a supplement for more than 4 to 6 weeks has not been thoroughly studied.
• Taking licorice together with diuretics (water pills) or other medicines that reduce the body's potassium levels could cause dangerously low potassium levels.
• People with heart disease or high blood pressure should be cautious about using licorice.
• When taken in large amounts, licorice can affect the body's levels of a hormone called cortisol and related steroid drugs, such as prednisone.
• Pregnant women should avoid using licorice as a supplement or consuming large amounts of licorice as food, as some research suggests it could increase the risk of preterm labor.
• Tell your health care providers about any herb or dietary supplement you are using, including licorice root. This helps to ensure safe and coordinated care.

Sources:

National Center for Complementary and Alternative Medicine. Hepatitis C and Complementary and Alternative Medicine: 2003 Update. National Center for Complementary and Alternative Medicine Web site. Accessed at nccam.nih.gov/health/hepatitisc on May 30, 2006.

Licorice (Glycyrrhiza glabra). In: Coates P, Blackman M, Cragg G, et al., eds. Encyclopedia of Dietary Supplements. New York, NY: Marcel Dekker; 2005:391-399.

Licorice. Natural Medicines Comprehensive Database Web site. Accessed on May 30, 2006.

Natural Standard Research Collaboration. Licorice (Glycyrrhiza glabra L.) and DGL (deglycyrrhizinated licorice). MedlinePlus Web site. Accessed at medlineplus.gov on May 30, 2006.

Licorice root. In: Blumenthal M, Goldberg A, Brinckman J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Lippincott Williams & Wilkins; 2000:233-239.

NCCAM Publication No. D318
June 2006