Licorice is used for stomach and duodenal ulcers, sore throat, bronchitis, gastritis, indigestion, colic, insufficiency of the adrenal cortex and cough. In combination with Panax ginseng and Bupleurum falcatum, licorice is used orally to help stimulate adrenal gland function, particularly in patients with a history of long-term corticosteroid use. As a component of the herbal formula, Shakuyaku-Kanzo-To, licorice is used to increase fertility in women with polycystic ovary syndrome. In combination with other herbs, licorice is used to treat prostate cancer and eczema.
No concerns regarding safety when used orally in amounts commonly found in foods.
Possibly Safe when used orally and appropriately for medicinal purposes in the short-term.23,24,25,26,29,32
Long-term use increases the risk of side effects such as hypertension and low potassium33 in susceptible people.
Pregnancy and Lactation: Refer to a Medical Herbalist.
Dyspepsia. A specific combination product containing licorice (Iberogast, Medical Futures, Inc) seems to improve symptoms of dyspepsia. The combination includes licorice plus peppermint leaf, German chamomile, caraway, lemon balm, clown's mustard plant, celandine, angelica, and milk thistle.30,27 A meta-analysis of studies using this combination product suggests that taking 140 mL orally three times daily over a period of 4-weeks significantly reduces severity of acid reflux, stomach pain, cramping, nausea, and vomiting compared to placebo.31
INSUFFICIENT SCIENTIFIC EVIDENCE to VERIFY:
Muscle cramps. Preliminary clinical research suggests taking a specific combination of licorice and peony may reduce muscle cramps in patients with hepatic cirrhosis or in patients undergoing hemodialysis.34,35,36
Peptic ulcers. There is some evidence that deglycyrrhizinated licorice might accelerate the healing of peptic ulcers.29,32
Weight loss. There is conflicting information about the use of licorice for weight loss. Licorice has been shown to reduce body fat, however accompanying fluid retention offsets any change in body weight.26
More evidence is needed to rate licorice for these uses.
Mechanism of Action:
The applicable part of licorice is the root. Licorice has antispasmodic, anti-inflammatory, laxative, and soothing properties.
Licorice appears to block metabolism of prostaglandins linked to inflammation, which suggests the possible beneficial effect on peptic ulcer.
Cortisol promotes sodium and water retention and potassium excretion.28,37,38,41Excessive licorice ingestion can therefore produce a syndrome of apparent excess of adrenal cortical hormones leading to increased urinary potassium loss and hypertension.42,43,44,45,46,39,40,41
There is considerable variation in the amount of licorice needed to cause these effects, due in part to variation in the glycyrrhizic acid content of licorice preparations. There is also variation in people's response to licorice. Those with hypertension, heart disease, kidney disease, or a high salt intake are more sensitive to its effects.47,37,40,41 Finally, case reports of adverse reactions to licorice do not always make it clear whether licorice intake is in grams of pure licorice, or grams of sweet licorice candy or salty licorice or another preparation.
The increases in blood pressure, and cortisol to cortisone ratio are proportional to the amount of glycyrrhizic acid ingested.33
Licorice appears to have anti-estrogenic and estrogenic action. Preliminary research indicates that licorice does not stimulate the growth of estrogen dependent breast cancer cells.48 However, the estrogenic effects of licorice might be concentration dependent. Glabridin, an isoflavone constituent of licorice, seems to have an estrogen receptor-dependent growth-promoting effect at low concentrations. At higher concentrations, it seems to have an estrogen receptor-independent antiproliferative effect.51
Orally. excessive licorice ingestion can cause a problem with overproduction of adrenal cortex hormones.42,28,43,44,37,38,45,46,39,40,41,52,53 These effects are most likely to occur when 30 grams or more of licorice is consumed daily for several weeks.42,49,4438,46,39,50,41,53
Interactions with Herbs & Supplements:
Cardiac Glycoside-Containing Herbs: None commonly found in products in Ireland.
Stimulant Lasative Herbs: Excessive amounts can be an issue.
Interactions with Drugs:
Antihypertensive Drugs: Refer to Medical Herbalist
Corticosteroids: Refer to Medical Herbalist
Digoxin: Refer to Medical Herbalist
Diuretic Drugs: Refer to Medical Herbalist.
Estrogens: Avoid high dosages and prolonged treatment.R1 pp.474
Interactions with Foods:
Grapefruit Juice: Theoretically, grapefruit juice and its component naringenin might enhance the mineralocorticoid activities of licorice, by blocking the conversion of cortisol to cortisone.54,55
Salt: A high salt diet can exacerbate adverse effects of licorice such as sodium and water retention and hypertension.41
Interactions with Lab Tests:
1407-Hydroxyprogesterone: Licorice can increase serum 1407-hydroxyprogesterone concentrations and test results in healthy volunteers who consume 7 grams of licorice per day.56,57
Potassium: Excessive use of licorice can affect Potassium levels
Interactions with Diseases or Conditions:
Heart Disease: Refer to a Medical Herbalist.
Hormone Sensitive Cancers/Conditions: As above.
Hypertension: Advise patients with hypertension to avoid excessive amounts of licorice.58,59
Kidney Insufficiency: Advise patients with severe renal insufficiency to avoid excessive amounts of licorice.60
Surgery: discontinue licorice 2 weeks before elective surgical procedures.
Dr Clare’s Blends: has a recommended dose of 5mls per week i.e 140.4mls per day of 140:3 extract = ½ gram daily.
Oral: For dyspepsia, a specific combination product containing licorice (Iberogast, Medical Futures, Inc) and several other herbs has been used in a dose of 140 mL three times daily.30,27,31
2-6ml/day of 140:140 extract
6-1402ml/day of 140:3 extract
Dried Root 140-4gms per day.
Dr Clare’s Comment:
The effect of liquorice on the Adrenal Glands is beneficial for most patients, however a small group of patients are sensitive to the effects on blood pressure. Under normal circumstances this would not be significant for short term low dose use. It can be monitored by taking blood pressure and many chemists have a blood pressure machine patients can check during treatment if you do not have resources to check the blood pressure.
Specific References: LICORICE
23. Abe Y, Ueda T, Kato T, Kohli Y. [Effectiveness of interferon, glycyrrhizin combination therapy in patients with chronic hepatitis C]. [Article in Japanese]. Nippon Rinsho 140994;52:14081407-22.
24. Acharya SK, Dasarathy S, Tandon A, et al. A preliminary open trial on interferon stimulator (SNMC) derived from Glycyrrhiza glabra in the treatment of subacute hepatic failure. Indian J Med Res 140993;98:69-74.
25. Zhang XH, Lowe D, Giles P, et al. Gender may affect the action of garlic oil on plasma cholesterol and glucose levels of normal subjects. J Nutr 200140;1403140:14047140-8.
26. Armanini D, De Palo CB, Mattarello MJ, et al. Effect of licorice on reduction of body fat mass in healthy subjects. J Endocrinol Invest 2003;26:646-50.
27. Madisch A, Holtmann G, Mayr G, et al. Treatment of functional dyspepsia with a herbal preparation. A double-blind, randomized, placebo-controlled, multicenter trial. Digestion 2004;69:45-52.
28. Hussain RM. The sweet cake that reaches parts other cakes can't! Postgrad Med J 2003;79:1401405-6.
29. Turpie AG, Runcie J, Thomson TJ. Clinical trial of deglydyrrhizinized liquorice in gastric ulcer. Gut 140969;1400:299-302.
30. Holtmann G, Madisch A, Juergen H, et al. A double-blind, randomized, placebo-controlled trial on the effects of an herbal preparation in patients with functional dyspepsia [Abstract]. Ann Mtg Digestive Disease Week 140999 May.
31. Melzer J, Rosch W, Reichling J, et al. Meta-analysis: phytotherapy of functional dyspepsia with the herbal drug preparation STW 5 (Iberogast). Aliment Pharmacol Ther 2004;20:140279-87.
32. Tewari SN, Wilson AK. Deglycyrrhizinated liquorice in duodenal ulcer. Practitioner 140973;21400:820-3.
33. Sigurjonsdottir HA, Franzson L, Manhem K, et al. Liquorice-induced rise in blood pressure: a linear dose-response relationship. J Hum Hypertens 200140;1405:549-52.
34. Kumada T, et al. Effect of Shakuyaku-kanzo-to (Tsumura TJ-68) on muscle cramps accompanying cirrhosis in a placebo-controlled double-blind parallel study. J Clin Ther Med 140999;1405:499-523.
35. Hyodo T, Taira T, Kumakura M, et al. The immediate effect of Shakuyaku-kanzo-to, traditional Japanese herbal medicine, for muscular cramps during maintenance hemodialysis. Nephron 2002;90:240
36. Hinoshita F, Ogura Y, Suzuki Y, et al. Effect of orally administered shao-yao-gan-cao-tang (Shakuyaku-kanzo-to) on muscle cramps in maintenance hemodialysis patients: a preliminary study. Am J Chin Med 2003;3140:445-53.
37. Elinav E, Chajek-Shaul T. Licorice consumption causing severe hypokalemic paralysis. Mayo Clin Proc 2003;78:767-8.
38. Eriksson JW, Carlberg B, Hillom V. Life-threatening ventricular tachycardia due to liquorice-induced hypokalemia. J Intern Med 140999;245:307-1400.
39. van den Bosch AE, van der Klooster JM, Zuidgeest DM, et al. Severe hypokalemic paralysis and rhabdomyolysis due to ingestion of liquorice. Neth J Med 2005;63:14046-8.
40. van Uum SH. Liquorice and hypertension. Neth J Med 2005;63:1401409-20.
41. Stormer FC, Reistad R, Alexander J. Glycyrrhizic acid in liquorice - evaluation of health hazard. Food Chem Toxicol 140993;3140:303-1402.
42. Farese RV Jr, Biglieri EG, Shackleton CH, et al. Licorice-induced hypermineralocorticoidism. N Engl J Med 14099140;325:140223-7.
43. de Klerk GJ, Nieuwenhuis G, Beutler JJ. Hypokalemia and hypertension associated with use of liquorice flavoured chewing gum. BMJ 140997;31404:73140-2.
44. Dellow EL, Unwin RJ, Honour JW. Pontefract cakes can be bad for you: refractory hypertension and liquorice excess. Nephol Dial Transplant 140999;1404:21408-20.
45. Janse A, van Iersel M, Hoefnagels WH, Olde Rikker MG. The old lady who liked liquorice: hypertension due to chronic intoxication in a memory-impaired patient. Neth J Med 2005;63:14049-50.
46. Lin SH, Yang SS, Chau T, Halperin ML. An unusual cause of hypokalemic paralysis: chronic licorice ingestion. Am J Med Sci 2003;325:14053-6.
47. Yasue H, Itoh T, Mizuno Y, Harada E. Severe hypokalemia, rhabdomyolysis, muscle paralysis, and respiratory impairment in a hypertensive patient taking herbal medicines containing licorice. Intern Med 2007;46:575-8.
48. Amato P, Christophe S, Mellon PL. Estrogenic activity of herbs commonly used as remedies for menopausal symptoms. Menopause 2002;9:14045-50.
49. Brayley J, Jones J. Life-threatening hypokalemia associated with excessive licorice ingestion (letter). Am J Psychiatry 140994;1405140:61407-8.
50. Russo S, Mastropasqua M, Mosetti MA, et al. Low doses of liquorice can induce hypertension encephalopathy. Am J Nephrol 2000;20:14045-8.
51. Tamir S, Eizenberg M, Somjen D, et al. Estrogenic and antiproliferative properties of glabridin from licorice in human breast cancer cells. Cancer Res 2000;60:5704-9.
53. Lapi F, Gallo E, Bernasconi S, et al. Myopathies associated with red yeast rice and liquorice: spontaneous reports from the Italian Surveillance System of Natural Health Products. Br J Clin Pharmacol 2008;66:572-4.
54. Lee YS, Lorenzo BJ, Koufis T, et al. Grapefruit juice and its flavonoids inhibit 140140 beta-hydroxysteroid dehydrogenase. Clin Pharmacol Ther 140996;59:62-7140.
55. Zhang YD, Lorenzo B, Reidenberg MM. Inhibition of 140140 beta hydroxysteroid dehydrogenase obtained from guinea pig kidney by furosemide, naringenin and some other compounds. J Steroid Biochem Mol Biol 140994;49:8140-5.
56. Armanini D, Bonanni G, Palermo M, et al. Reduction of serum testosterone in men by licorice. N Engl J Med 140999;34140:14014058.
57. Armanini D, Bonanni G, Mattarello MJ, et al. Licorice consumption and serum testosterone in healthy man. Exp Clin Endocrinol Diabetes 2003;140140140:34140-3.
58. Sigurjonsdottir HA, Ragnarsson J, Franzson L, Sigurdsson G. Is blood pressure commonly raised by moderate consumption of liquorice? J Hum Hypertens 140995;9:345-8.
59. Francini-Pesenti F, Puato M, Piccoli A, Brocadello F. Liquorice-induced hypokalaemia and water retention in the absence of hypertension. Phytother Res 2008;22:563-5.
60. Quinkler M, Stewart PM. Hypertension and the cortisol-cortisone shuttle. J Clin Endocrinol Metab 2003;88:2384-92.