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Supplement Forms/Alternate Names:

Licorice root, liquorice, sweet root, gan cao, gan-zao, Chinese licorice, glycyrrhizin, licorice flavonoid oil


Licorice is a plant that is used to flavor food and candy. The root has been used to ease sore throat and cough when taken as a lozenge or used as a mouthwash. Licorice has also been used to lower body mass index (BMI). It can be taken as a pill, powder, or extract. Licorice can also be made into a tea or oil.


100 to 300 milligrams oil or one lozenge once daily

What Research Shows

May Be Effective

  • Helicobacter pylori infection —may help fight infection quicker when used with standard treatment A1, A2
  • Postoperative sore throat —may ease pain and improve cough when gargled or taken as a lozengeB1-B5

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Safety Notes

It is likely safe to use licorice products on the skin. It is also likely safe for most adults to take licorice for a short time, but it may raise blood pressure. It is not safe to take high doses of licorice or small doses over an extended time by women who are pregnant or breastfeeding.C1-C5


Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse, such as:

  • People with depression should talk to their doctor before taking licorice. It may interact with their medicines.
  • People taking medicine to prevent blood clots should talk to their doctors before taking licorice. It may increase the risk of bleeding.
  • People taking medicine to increase urine flow should talk to their doctor before taking licorice. It may interact with the medicine.


A. Helicobacter Pylori Infection

A1. Hajiaghamohammadi AA, Zargar A, Oveisi S, Samimi R, Reisian S. To evaluate of the effect of adding licorice to the standard treatment regimen of Helicobacter pylori. Braz J Infect Dis. 2016 Nov - Dec;20(6):534-538.

A2. Penninkilampi R, Eslick EM, et al. The association between consistent licorice ingestion, hypertension and hypokalaemia: a systematic review and meta-analysis. J Hum Hypertens. 2017;31(11):699-707.

B. Postoperative Sore Throat

B1. Agarwal A, Gupta D, et al. An evaluation of the efficacy of licorice gargle for attenuating postoperative sore throat: a prospective, randomized, single-blind study. Anesth Analg. 2009 Jul;109(1):77-81.

B2. Gupta D, Agrawal S, et al. Effect of preoperative licorice lozenges on incidence of postextubation cough and sore throat in smokers undergoing general anesthesia and endotracheal intubation. 2013;22(2):173-178.

B3. Ruetzler K, Fleck M, et al. A randomized, double-blind comparison of licorice versus sugar-water gargle for prevention of postoperative sore throat and postextubation coughing. Anesth Analg. 2013 Sep;117(3):614-621.

B4. Honarmand A, Safavi M, et al. The efficacy of different doses of liquorice gargling for attenuating postoperative sore throat and cough after tracheal intubation. Eur J Anaesthesiol. 2016;33(8):595-596.

B5. Hajiaghamohammadi AA, Zargar A, et al. To evaluate the effect of adding licorice to the standard treatment regimen of Helicobacter pylori. Braz J Infect Dis. 2016;20(6):534-538.

C. Safety

C1. Räikkönen K, Seckl JR, et al. Maternal prenatal licorice consumption alters hypothalamic-pituitary-adrenocortical axis function in children. Psychoneuroendocrinology. 2010 Nov;35(10):1587-1593.

C2. Tsai HH, Lin HW, et al. A review of potential harmful interactions between anticoagulant/antiplatelet agents and Chinese herbal medicines. PLoS One. 2013 May 9;8(5):e64255.

C3. Feng X, Ding L, et al. Potential drug interactions associated with glycyrrhizin and glycyrrhetinic acid. Drug Metab Rev. 2015 May;47(2):229-238.

C4. Kristanc L, Kreft S. European medicinal and edible plants associated with subacute and chronic toxicity part I: Plants with carcinogenic, teratogenic and endocrine-disrupting effects. Food Chem Toxicol. 2016 Jun;92:150-64.

C5. Nazari S, Rameshrad M, et al. Toxicological Effects of Glycyrrhiza glabra (Licorice): A Review. Phytother Res. 2017 Nov;31(11):1635-1650.

Last reviewed March 2020 by EBSCO NAT Review Board Eric Hurwitz, DC  Last Updated: 6/22/2020