Licorice Side Effects and Benefits
Gan Cao 甘草
licorice root, licorice, liquorice, sweet root, gan zao (Chinese licorice), Glycyrrhiza glabra, Glycyrrhiza uralensis (Chinese

Most licorice is grown in Greece, Turkey, and Asia. Licorice contains a compound called glycyrrhizin (or glycyrrhizic
acid).Licorice root has been used as a dietary supplement, it may have benefit on people at risk of 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").
Scientific Evidence

Licorice root extracts may benefit people at risk of certain cancers. Isoangustone A, a novel flavonoid from licorice root,
was found to be able to suppresse the proliferation of human melanoma cells.  Isoangustone A significantly blocked cell
cycle progression at the G1 phase and inhibited the expression of G1-phase regulatory proteins.  In a xenograft mouse
model, IAA significantly decreased tumor growth, volume, and weight of SK-MEL-28 xenografts.[1] More studies are
needed to verify this benefit claim.

Cognitive Functions - Memory and Learning
Licorice root extracts may benefit people at risk of certain cognitive conditions such as amnesia. Amnesia is a a deficit in
memory caused by brain damage, disease, or psychological trauma. Four doses (75, 150, 225, and 300 mg/kg) of
aqueous extract of licorice root was administered to rats orally for six successive weeks.Results showed that all the
doses of aqueous root extract of licorice significantly enhanced the memory; however, in the doses of 150 and 225
mg/kg, it showed a significant enhancement in learning and memory. Furthermore, Diazepam-induced amnesia was
reversed by the aqueous root extract of licorice. [2] Though the animal studies are promising, clinical studies are
needed to support this potential benefit-claim of licorice root.

Dental Caries
Dental Caries are localized destruction of the tooth surface initiated by decalcification of the enamel followed by
enzymatic lysis of organic structures and leading to cavity formation. In a study, the mean mutans streptococci colony
counts in three groups after mouthwash with aqueous liquorice, ethanolic liquorice and chlorhexidine gluconate
(0.156%) were compared. The reduction in mutans streptococci colony counts was significant after mouthwash with
ethanolic liquorice as compared to mouthwash wtih chlorhexidine gluconate (0.156%). Liquorice extracts also led to an
immediate rise in salivary pH. The results showed an immediate antimicrobial action of liquorice extracts, with limited
retentivity. The study suggests that both aqueous and ethanolic liquorice extracts are potent cariostatic agents.
However, more studies are needed to confirm this benefit claim of licorice root mouthwash. [3]

Hepatitis C
A review of several clinical trials found that glycyrrhizin might reduce complications from hepatitis C in some patients.  In
recent animal study, glycyrrhizin injected alone or in combination with DHV vaccine protected or ameliorated the
deteriorating effects induced by DHV vaccine and/or duck hepatitis virus infection by improvement of erythrogram and
leukogram, as well as liver and kidney functions. [4]

Metabolic syndrome
Licorice root extracts may offer benefits to people at risk of metabolic syndrome. Metabolic syndrome is a cluster of
metabolic risk factors for cardiovascular disease and Type 2 diabetes mellitus. The major components of metabolic
syndrome include excess abdominal fat; atherogenic dyslipidemia, hypertension; hyperglycemia; insulin resistance; a
proinflammatory state; and a prothrombotic (thrombosis) state. In an animal study, metabolic syndrome was induced by
feeding a fructose-enriched (60%) diet for six weeks, after which single dose of glycyrrhizin (the important active in
licorice root extract, 50 mg/kg body weight) was administered intraperitoneally. Glycyrrhizin was found to reduce the
enhanced levels of blood glucose, insulin and lipids in metabolic syndrome group. [5]

Licrorice root may benefit people at risk of seizure. Seizure is a clinical or subclinical disturbance of cortical function due
to a sudden, abnormal, excessive, and disorganized discharge of brain cells. Recurrent seizures are usually referred to
as epilepsy or "seizure disorder." Ethanol extract of licorice root was found to delay the onset of seizure in rats. But the
duration of convulsion was reduced only in higher dose level (200 and 400 mg/ kg), The researchers also prepared an
aqueous licorice root extract, but it did not work as good as the ethanol extract. [6] Licrorice root is a supplement, not a
medicine. Though licrorice root extract may benefit people at risk of seizure, users at risk/suffered from seizure must
consult a medical doctor for a proper medical treatment.

Licorice Root Side Effects

The side effects of licorice root extracts can be serious, and the side effects are potentially related to glycyrrhizin.
Glycyrrhizin, a triterpene compound, is the most abundant constituent of dried licorice root. However, high intake or
long-term consumption of glycyrrhizin causes several side effects, such as hypertension, hypertensive encephalopathy,
and hypokalemia. [1] Because of its biomedical properties, taking licorice together with diuretics (water pills) or other
medicines that reduce the body potassium levels could lead to dangerously low potassium levels. People with heart
disease or high blood pressure should avoid licorice.

Taking high doses of licorice root extracts may also lead other serious side effects, as licorice root extracts may affect
the body's levels of a hormone called cortisol, related steroid drugs, such as prednisone. Pregnant women should also
avoid licorice root extracts, as it may lead unwanted side effect - preterm labor.



National Center for Complementary and Alternative Medicine. Hepatitis C and Complementary and Alternative Medicine
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 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.

[1] Song NR et al, Isoangustone A, a novel licorice compound, inhibits cell proliferation by targeting PI3-K, MKK4 and
MKK7 in human melanoma. Cancer Prev Res (Phila). 2013 Oct 8. [2] Chakravarthi KK, Avadhani R. Beneficial effect of
aqueous root extract of Glycyrrhiza glabra on learning and memory using different behavioral models: An experimental
study. J Nat Sci Biol Med. 2013 Jul;4(2):420-425. [3] Jain E, et al, Liquorice root extracts as potent cariostatic agents in
pediatric practice. J Indian Soc Pedod Prev Dent. 2013 Jul-Sep;31(3):146-52. [4] Okda FA, et al, Some Haematological
and Biochemical Investigations on Duck Virus Hepatitis following Administration of Glycyrrhizin. ISRN Pharmacol. 2013
Jul 30;2013:849412. [5] Sil R, et al, Glycyrrhizin ameliorates insulin resistance, hyperglycemia, dyslipidemia and
oxidative stress in fructose-induced metabolic syndrome-X in rat model. Indian J Exp Biol. 2013 Feb;51(2):129-38. [6]
Chowdhury B, et al, Anti-convulsant action and amelioration of oxidative stress by Glycyrrhiza glabra root extract in
pentylenetetrazole- induced seizure in albino rats. Indian J Pharmacol. 2013 Jan-Feb;45(1):40-3.