A Review of the Pharmacological Efficacy and Safety of Licorice Root from Corroborative Clinical Trial Findings

J Med Food. 2020 Jan;23(1):12-20. doi: 10.1089/jmf.2019.4459. Epub 2019 Dec 23.


Since ancient times, licorice, the root of Glycyrrhiza glabra, has been known to have a wide spectrum of therapeutic effects. Glycyrrhizin is cleaved to glycyrrhizic acid, which is subsequently converted to glycyrrhetic acid by human intestinal microflora. Glycyrrhetic acid is a potent inhibitor of 11β-hydroxysteroid dehydrogenase (11β-HSD) and performs a range of corticosteroid-like activities. The pharmacologic effects of licorice contribute to its anti-inflammatory, antioxidative, anti-allergenic, and antimicrobial properties. Licorice has been used to treat liver disease, gastrointestinal disorders, oral disease, and various skin disorders and has been used in gum, candy, herbs, alcoholic beverages, and food supplements. Licorice and its extracts, especially glycyrrhizin, can be taken orally, through the skin (in the form of gels and oils), and intravenously. Licorice demonstrates mineralocorticoid-like activity not only by inhibiting 11β-HSD2, but also by binding to a mineralocorticoid receptor, leading to potentially adverse risks of mineralocorticoid-like overactivity. Chronic use of licorice can lead to hypokalemia and hypertension, and some people are more sensitive to licorice exposure. Based on clinical trials, this review summarizes the positive effects of licorice and other reported side effects.

Keywords: 11-hydroxysteroid dehydrogenase; glycyrrhizic acid; glycyrrhizin; licorice.

Publication types

  • Review

MeSH terms

  • 11-beta-Hydroxysteroid Dehydrogenase Type 2 / antagonists & inhibitors
  • Antioxidants / pharmacology
  • Clinical Trials as Topic
  • Enzyme Inhibitors / pharmacology
  • Glycyrrhetinic Acid / adverse effects
  • Glycyrrhetinic Acid / pharmacology*
  • Glycyrrhiza / chemistry*
  • Glycyrrhizic Acid / adverse effects
  • Glycyrrhizic Acid / pharmacology*
  • Humans
  • Plant Extracts / adverse effects
  • Plant Extracts / pharmacology*
  • Plant Roots / chemistry*


  • Antioxidants
  • Enzyme Inhibitors
  • Plant Extracts
  • Glycyrrhizic Acid
  • 11-beta-Hydroxysteroid Dehydrogenase Type 2
  • Glycyrrhetinic Acid