Summary

Licorice (Glycyrrhiza spp.) includes numerous species native to Europe, Asia and the Americas with only a few species currently used in medicine. The Greek physician Dioscorides derived the name from glukos (sweet) and riza (root). The roots contain glycyrrhizin, a triterpenoid glycoside about 50 times sweeter than sucrose. Glycyrrhizin inhibits the breakdown of cortisol to cortisone and thus potentiating its effects. Licorice benefits people suffering from adrenal fatigue and to reduce drug withdrawal symptoms from discontinuing prednisone. However, excess use ( > 20g per day) of licorice causes " pseudo-aldosteronism " because glycyrrhizin impairs the excretion of sodium and water loss leading to hypertension as well as potassium loss.

Western herbalists recommend European licorice (Glycyrrhiza glabra) tea as a demulcent to soothe mucous membranes of the gastrointestinal (ulcers, heartburn) and respiratory tract (a cough, infections, asthma). Animal studies demonstrate that licorice contains licoflavone, a flavonoid that increases the prostaglandin PGE2 to stimulate mucus production. Deglycyrrhizinated licorice (DGL) lacks the steroid-sparing glycyrrhizin and therefore treats heartburn without the risk of hypertension.

Licorice increases mucous production in the respiratory tract to help protect inflamed airways and also dissolve phlegm making it easier to expectorate. Research demonstrates glycyrrhizin has potent antiviral activity against several types of viruses, including Influenza A, SARS, H1N1, herpes (HSV) and hepatitis.

Asian herbalists add Chinese licorice (Glycyrrhiza uralensis) to a significant number of herbal formulas to enhance the activity of other ingredients and improve the taste of decoctions. Although it possesses numerous medical properties, Chinese herbalist rarely prescribed it alone.

Indications

Endocrine
• stress
• adrenal fatigue
• adreno-corticoid insufficiency
• Addison's disease
• pancreatitis

Gastrointestinal
• inflammation of GI tract
• esophagitis
• gastroesophageal reflux disorder (GERD)
• gastritis
• laryngitis
• gastric ulcers
• apthous ulcers

Immune
• viruses
• herpes simplex virus (HSV)
• shingles
• influenza
• human immunodeficiency virus (HIV)
• severe acute respiratory syndrome (SARS)
• hepatitis (HAV, HBV, HCV)
• Epstein-Barr virus (EBV) - mononucleosis
• cancer
• leishmaniasis

Cardiovascular
• hypotension

Reproduction
• polycystic ovary syndrome (PCOS) - in combo with chinese peony
-
• infertility
• hirsutism
• menopausal hot flashes

Other
• eczema
• acne rosacea

Actions

• Adrenal Tonic
• Antiviral
• Antiulcerogenic
• Expectorant
• Demulcent
• Antitussive
• Antiinflammatory
• Hepatoprotective
• Hypertensive
• Phytoestrogen

Constituents

• Triterpene Glycoside (Glycyrrhizinic Acid, Glycyrrhetinic Acid)
• Flavenoids
• Isoflavonoids
• Polysaccharides

Posology

• Tincture (1:5 in 40% EtOH): 1-3 ml tid
• Fluid extract (1:1 in 40% EtOH): 2-4 ml daily
• Decoction (dried powdered root): 0.5-1 tsp tid

Safety

• Long-term use: large amounts should not be taken for longer than 6-8 weeks.

• Pseudohyperaldosteronism • chronic use may cause symptoms of hyperaldosteronism including: hypertension, hypokalemia, weak muscles, dizziness, edema.

• Blood pressure • should be used with caution in patients with hypertension.

• Pregnancy & lactation: should be used with caution.

Note: Deglycerized licorice (DGL) does not cause affect cortisol and therefore does not cause pseudohyperaldosteronism. It can not be used to tonify the adrenals but still has a benefit for GERD, ulcers and gastritis.

Interactions

Contra-indicated with the following medication that also cause hypokalemia:
• loop diuretics
• thiazide diuretics
• cardiac glycosides
• antiarrhythmic drugs

Caution in patients taking:
• stimulating laxatives (anthraquinones)
• corticosteroids
• MOA-inhibitors

References

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Barnes J, Anderson LA, Phillipson JD. Herbal Medicines, 3rd ed. London: Pharmaceutical Press, 2007.

Bone K. Principles and Practice of Phytotherapy. Edinburgh: Churchill Livingstone, 2000.

Bone K. A Clinical Guide to Blending Liquid Herbs: Herbal Formulations for the Individual Patient. St Louis, MO: Churchill Livingstone, 2003.

Brinker F. The Toxicology of Botanical Medicines, 3rd ed. Sandy, Oregon: Eclectic Medical Publications, 2000.

Felter HW, Lloyd JU. King's American Dispensatory. 1898. http://www.ibiblio.org/herbmed/eclectic/kings/main.html. Accessed: August 19, 2006.

Hoffman D. Medical Herbalism. Rochester, Vermont: Healing Arts Press, 2003.

Weiss RF. Herbal Medicine. Beaconsfield, England: Beaconsfield Publishers Ltd, 1988.

Williamson EM, ed. Major Herbs of Ayurveda. Edinburgh: Churchill Livingstone, 2002