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This fact sheet provides basic information about licorice root—common names, what the science says, potential side effects and cautions, and resources for more information.
Most licorice is grown in Greece, Turkey, and Asia. Licorice contains a compound called glycyrrhizin (or glycyrrhizic acid). Licorice has a long history of medicinal use in both Eastern and Western systems of medicine. Today, licorice is used as a folk or traditional remedy for stomach ulcers, bronchitis, and sore throat, as well as infections caused by viruses, such as hepatitis.
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
- An injectable form of licorice extract—not available in the United States—has been shown to have beneficial effects against hepatitis C in clinical trials. There are no reliable data on oral forms of licorice for hepatitis C. More research is needed before reaching any conclusions.
- There are not enough reliable data to determine whether licorice is effective for any condition.
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 dietary supplement for more than 4 to 6 weeks has not been thoroughly studied.
- Taking licorice together with diuretics (water pills), corticosteroids, 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 all your health care providers about any complementary health approaches you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care. For tips about talking with your health care providers about complementary health approaches see NCCIH's Time to Talk campaign.
For More Information
The NCCIH Clearinghouse provides information on NCCIH and complementary health approaches, including publications and searches of Federal databases of scientific and medical literature. The Clearinghouse does not provide medical advice, treatment recommendations, or referrals to practitioners.
A service of the National Library of Medicine (NLM), PubMed® contains publication information and (in most cases) brief summaries of articles from scientific and medical journals.
Office of Dietary Supplements (ODS), National Institutes of Health (NIH)
ODS seeks to strengthen knowledge and understanding of dietary supplements by evaluating scientific information, supporting research, sharing research results, and educating the public. Its resources include publications (such as Dietary Supplements: What You Need to Know), fact sheets on a variety of specific supplement ingredients and products (such as vitamin D and multivitamin/mineral supplements), and the PubMed Dietary Supplement Subset.
PubMed Dietary Supplement Subset: ods.od.nih.gov/Research/PubMed_Dietary_Supplement_Subset.aspx
NIH National Library of Medicine's MedlinePlus
- Armanini D, Fiore C, Bielenberg J. 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 at www.naturaldatabase.com on July 15, 2009.
- Licorice (Glycyrrhiza glabra L.) and DGL (deglycyrrhizinated licorice). Natural Standard Database Web site. Accessed at www.naturalstandard.com on July 15, 2009.
- Licorice root. In: Blumenthal M, Goldberg A, Brinckman J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Lippincott Williams & Wilkins; 2000:233–239.
- National Center for Complementary and Integrative Health. Hepatitis C: A Focus on Dietary Supplements. National Center for Complementary and Integrative Health Web site. Accessed at nccih.nih.gov/health/hepatitisc on June 3, 2010.
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