Licorice, in general, has been used for ailments of the gastrointestinal and respiratory tracts. Licorice has been used in traditional Chinese medicine (TCM) for over 3,000 years as a tonic to rejuvenate the heart and spleen and as a treatment for ulcers, cold symptoms, and skin disorders. In Ayurvedic medicine, it is used internally for gastric ulcers, headaches, bronchitis, eye disease, and sore throat. Externally, it has been used for wounds and cuts. Folk medicine uses include for appendicitis and constipation, and to increase milk production. It has also been used for epilepsy.
Modern herbalists commonly use licorice to treat adrenal insufficiencies such as hypoglycemia, to counteract stress, and to purify the liver and blood. This herb is also used to counter severe allergic reactions and to treat rheumatoid arthritis. It is approved by the German Commission E for coughs and bronchitis and ulcers of the stomach and duodenum.
Spanish licorice; Russian licorice, liquorice; réglisse (French); Lakritze, Süssholz (German); Spanish Juice, Black Sugar, Liquorice; Radix Liquiritiae (root), Succus Liquiritiae (extract); Arpsous, Arq-sous (Arabic); Jashtimodhu (Bengali); Noekiyu (Burmese); Kan tsau, Gancao (Chinese); Lakrids, Lakridsplante (Danish); Zoethout (Dutch); Lagritsa-magusjuur (Estonian); Shirin bajan (Farsi); Lakritskasvi, Lakritsi (Finnish); Süßholz (German); Glikσriza, Jiαmpoli (Greek); Jethimadh (Gujrati); Jethimadh, Mulhathi (Hindi); Édesfa, Igazi édesgyökér (Hungarian); Lakkrís (Icelandic); Liquirizia (Italian); Kanzou (Japanese); Yasthimadhuka (Kannada): Sa em (Laotian); Yashtimadhukam (Malayalan); Jesthamadha (Marathi); Lakrisrot (Norwegian); Lukrecja gladka (Polish); Muleti (Punjabi); Lakrichnik (Russian); Madhuka, Yashtimadhu (Sanskrit); Atimaduram (Singhalese); Orozuz, Ragaliz (Spanish); Susu (Swahili); Lakrits (Swedish); Atimaduram (Tamil); Atimadhuramu (Telugu); regaliz, Yerba Dulce, Palo Cuate, Coahtli
Licorice has been used medicinally for many centuries; the ancient Egyptians, Greeks and Romans, all recognised how beneficial it was for coughs, colds and chills. Licorice was often called scythic by the ancients because of the Scythians, redoubtable warriors were reputed to be able to go for ten days without other food or water by eating licorice. Licorice has been used medicinally since at least 500 B.C. and still features in official pharmacopoeia as a “drug” for stomach ulcers. G. glabra originates in the Mediterranean and the Middle East and has been cultivated in Europe since at least the 16th century.
In China, G. uralensis or gan cao is used; it is called the “great detoxifier” and is thought to drive poisons from the system. It is also a valuable tonic, often called “the grandfather of herbs.” The roots became popular chewing sticks in Italy, Spain, the West Indies, and other places where the plant grows. Liquorice has an ancient reputation as an aphrodisiac; the Kama Sutra and Ananga Ranga contain numerous recipes for increasing sexual vigour which include licorice.
HPO regulator, choleretic, cytoprotective, anti-inflammatory (urinary), anti-inflammatory (GIT), antiasthmatic, adaptogen, adrenal restorative, aldose reductase inhibitor, anti-inflammatory, antiseptic (urinary), antispasmodic (muscles), antispasmodic (respiratory tract), antispasmodic (uterus), antitussive, antiulcerogenic (GIT), antiviral (topically), blood sugar regulating, demulcent, expectorant (relaxing), hypertensive, laxative, oestrogenic, taste improver
Endocrine disorders including endometriosis, ovarian cyst, polycystic ovarian syndrome, androgen excess, Addison’s disease, respiratory conditions including asthma, bronchitis, cough, sore throat (gargle), skin disorders including eczema, psoriasis and acne (topically), gastrointestinal disorders including gastritis, ulcer, irritable bowel syndrome, constipation, steroids to augment treatment with stress.
Licorice contains a flavonoid, licochalcone-A, which has been shown to kill cancer cells of acute leukaemia and of the breast and prostate. This compound works by lowering the level of bcl-2, a protein that causes resistance to anticancer drugs. More work is needed to see if licorice can be used with anticancer drugs to make them more useful. This flavonoid also may be protective against developing cancer. The most useful forms of treatment for cancer using licorice, however, are Chinese herbal formulas containing licorice and other herbs.
Gastritis and peptic ulcer.
Licorice is useful for many digestive disorders. It soothes inflammation and protects the stomach and intestines from the effects of stomach acid. Unlike many ulcer drugs, glycyrrhizinic acid does not reduce acid production in the stomach, which would result in incomplete digestion. Instead, it increases the stomach’s defence mechanisms by fortifying the stomach’s protective mucous coating. Glycyrrhizinic acid also improves circulation to the cells lining the intestinal wall, boosting their supply of nutrients and oxygen.
Pure glycyrrhizinic acid can cause the retention of sodium and water. Deglycyrrhizinated licorice (DGL), which has no known side effects, is now available as well. DGL inhibits gastric juice secretion and protects the lining of the stomach from aspirin-induced damage. Two controlled studies suggest that regular use of DGL, in the form of a product that also contains antacids, can heal ulcers as effectively as drugs in the ranitidine (Zantac) family. In one study, another compound in licorice, carbenoxolone, was administered as 300 milligrams daily for one week followed by half that amount for five more weeks. Compared to an anti-ulcer medicine called pirenzepine, both healed ulcers in about 50 percent of the patients. However, newer drugs called H2 blockers have higher success rates. In another study, participants with dyspepsia (upset stomach) who were given licorice root as the significant ingredient along with other herbs such as peppermint leaves and caraway over twelve weeks showed improved symptoms by 43 percent compared to only 3 percent in the placebo group. Medical treatments try to prevent the recurrence of ulcers permanently by killing Helicobacter pylori bacteria. According to laboratory research, flavonoids in licorice appear to inhibit H. pylori, although this has not been shown in human studies to be effective. One study reported fewer recurrences of ulcers among people taking DGL as compared with those taking the drug cimetidine (Tagamet).
One component of licorice, glycyrrhizin, stimulates interferon gamma produced by immune cells, which acts against viral infections. In particular, it suppresses the secretion of the hepatitis B virus surface antigens in patients with hepatitis B. The licorice compound is thought to bind to liver cells to inhibit the proliferation of the virus. Minor Bupleurum Decoction, a Chinese formula that uses licorice, is also effective against hepatitis B, particularly in children.
Glycyrrhizin has been employed in the treatment of hepatitis C. Using an intravenous preparation of glycyrrhizin, and other compounds such as Stronger Neo-Minophagen C (NMC) was shown to improve the liver function of patients with hepatitis C and alcoholic cirrhosis. However, when treatment was stopped, the virus came back.
HIV/AIDS, cytomegalovirus, severe acute respiratory syndrome (SARS).
In one study, when the licorice compound glycyrrhizin was given intravenously to people with AIDS, HIV became undetectable after three treatments. There is some question as to the sensitivity of the antigen tests the researchers used to test for the presence of HIV. However, the researchers thought that licorice acted by keeping HIV from multiplying. In another study, forty-two HIV-positive people with haemophilia took glycyrrhizin along with two amino acids. The viral load in these individuals did not drop into the undetectable range, but they did experience relief from oral yeast infections, swollen lymph nodes, and rashes. Their immune and liver function also improved. Some Japanese physicians have experimented with licorice as a means of keeping HIV infection from progressing to full-blown AIDS, but there is not enough research to date to support its use for this purpose. Today, the proper use of drugs can reduce viral loads effectively in most patients. In infants with cytomegalovirus (CMV) who were administered an intravenous preparation of glycyrrhizin from licorice, the virus was eradicated from the blood and liver tests were normalised. In cell line studies, glycyrrhizin had potent antiviral effects against SARS. No human data are available for licorice and SARS, however.
Glycyrrhizin stops the production of toxic free radicals by acting as an antioxidant. Other components in licorice, such as licoricidin and glabridin, work as anti-inflammatories. These substances reduce swelling of the bronchial passageways to help with bronchitis and possibly asthma. The herb also stimulates the secretion of mucus in the windpipe, which relieves a dry cough. Licorice also increases the effectiveness of steroid drugs, which effectively treat a variety of inflammatory conditions but also produce some side effects. Clinical studies have shown that glycyrrhizin supplements prednisolone therapy, used in both asthma and lupus, allowing affected individuals to use smaller doses of prednisolone with fewer side effects. Similarly, licorice extends the useful life of cortisone creams used to treat vitiligo, a disorder that causes the skin to lose its pigmentation.
Chronic fatigue syndrome (CFS)
Epidemiologists have noted that some people who have CFS also have low blood pressure and other blood-pressure anomalies. This condition stems from adrenal-hormone deficiencies that cause the body to lose both sodium and water, resulting in drops in both blood volume and blood pressure. Licorice can reverse this process. Glycyrrhizinic acid, a chemical related to glycyrrhizin, blocks the activity of an enzyme that destroys the adrenal hormone cortisol. Higher cortisol levels in the bloodstream cause the kidneys to retain more sodium, and with it more water. This leads to higher blood pressure.
Diaper rash, skin irritations
Licorice contains glycyrrhizin, glycyrrhizic acid, and liquiritin, which have anti-inflammatory effects. Therefore, it is possible that licorice can ease inflammatory skin conditions to speed healing and relieve pain.
- Well-controlled clinical trials have shown DGL (2.3 to 3.8 g/day for 12 to 16 weeks) combined with antacids is as efficacious at healing gastric and duodenal ulcers as carbenoxolone, cimetidine, and ranitidine.
- Early uncontrolled trials demonstrated the curative effects of licorice on peptic ulcers. Unfortunately, a high percentage of patients developed side effects associated with sodium retention. In one trial, approximately 7 g of licorice juice-paste was administered daily. Side effects might have been countered by a low-sodium diet unless the patient was taking doses more than 40 g of licorice daily.
- Licorice extract demonstrated a dramatic effect in maintaining electrolyte equilibrium in patients with Addison’s disease. The daily dose ranged from 10 to 30 g of licorice extract. If adrenal cortex function was severely impaired, licorice was not a suitable treatment on its own but had a synergistic action with cortisone.
- In uncontrolled studies, licorice combined with white peony lowered the LH/FSH ratio, reduced ovarian testosterone production, and induced regular ovulation in patients with polycystic ovary syndrome. This combination contained equal amounts of licorice and white peony. Doses equivalent to 4 to 8 g per day of each herb were prescribed for 2 to 24 weeks.
- Licorice and white peony combination is approved for use in clinical practice in Japan and has been used to treat acute muscle cramps and dysmenorrhea. Doses equivalent to 6 g per day of each herb are prescribed. 8
- A substantial and significant drop in serum testosterone and a smaller significant increase in 17-hydroxyprogesterone was observed in a clinical study in which seven normal men received 7 g per day of a licorice extract containing 0.5 g of GL. Serum androstenedione was also raised, but the difference did not achieve statistical significance. 9 The possibility exists that excessive intake of licorice may cause decreased libido, but this is unlikely to result from its informed use as a therapeutic agent at the doses recommended in this monograph. In a more recent clinical trial, researchers twice failed to replicate the previously listed results. The authors identified differences between their methods and those of the previous study and possible statistical anomalies (including inappropriate use of statistical tests) in the earlier report. 10
- In an uncontrolled trial, Glyke (a patented preparation made from G. uralensis ) improved the T-lymphocyte CD4/CD8 ratio and CD4 counts in patients with HIV. An oral dose of 120 mg per day was given for 3 to 6 months. In an open study, HIV-positive haemophiliacs treated with GL (150 to 225 mg/day for 3 to 7 years) remained asymptomatic, but untreated controls showed decreases in T-lymphocyte counts.
- Results of a clinical trial in which GL was administered intravenously to haemophiliacs with AIDS suggest that GL by this route might inhibit HIV-1 replication in vivo.
- In a small uncontrolled study, GL (150 mg/day) was observed to be a safe treatment for hyperkalemia resulting from selective hypoaldosteronism in non-insulin–dependent diabetes mellitus. This dose of GL correlates to approximately 3 to 5 g per day of licorice.
- The successful treatment of chronic fatigue syndrome by licorice was reported in a case study. The daily dose of licorice was dissolved in milk (2.5 g/500 ml).
- Improvement of mouth ulcers was seen after 1 day, with complete healing in 3 days, when DGL was used in an uncontrolled trial. Patients were advised to gargle four times daily for 7 days with powdered DGL (200 mg per capsule) dissolved in 200 ml of warm water. In a double-blind, crossover trial, a carbenoxolone mouthwash significantly reduced the number of recurrent ulcers and associated discomfort.
- A controlled trial found GL application after 3 days reduced dental plaque. One side of the mouth was treated, and the other side served as the control.
- The antiviral drug idoxuridine (0.2%) incorporated in a GL gel was significantly better than a regular 0.5% idoxuridine ointment at reducing pain and increasing healing in patients with herpes lesions of the lips and nose. Carbenoxolone cream was better than placebo for treating initial and recurrent herpes genitalis in a double-blind study.
- An ointment containing crude licorice powder yielded good results in treating chronic eczema. Topical application of licorice extract demonstrated appreciable activity in patients with melasma (increased melanin pigmentation).
- In Germany, the Commission E supports using licorice to treat catarrh of the upper respiratory tract and gastric and duodenal ulcers.
Dosage (Divided Daily)
• Dried Powder: 3,000 – 15,000mg
• Liquid Extract: 3 – 15mL (1:1 liquid extract)
Do not administer during pregnancy, cardiovascular-related disorders such as hypertension, congestive heart failure and fluid retention, renal disorders, cholestatic or inflammatory liver disorders, hypokalaemia, hypotonia, anorexia nervosa and severe obesity.
Patients who are prescribed high glycyrrhizin licorice preparations for prolonged periods should be placed on a high-potassium, low-sodium diet and closely monitored for blood pressure increases and weight gain. Hypokalemia is the greatest threat and can occur at relatively low doses. Special precautions should be taken with elderly patients and patients with hypertension or cardiac, renal, or hepatic disease. These individuals should not receive licorice preparations high in glycyrrhizin (GL) for prolonged periods.
Interactions with other drugs
Avoid with beta blockers and other hypotensive medication (Enalapril, Peridopril, Atenolol, Amlodipine). Long-term use may elevate blood pressure, reducing drug efficacy. Licorice may increase potassium excretion, therefore avoid with digoxin (Lanoxin, Sigmaxin), potassium depletion may increase digoxin toxicity. May decrease metabolism and thus potentiate the effect of cortisone and prednisolone (Cortate, Presolone, Solone): use with caution to avoid corticosteroid excess. Avoid with thiazide (potassium-depleting diuretics including Accuretic and Amizide). A constituent of licorice has demonstrated potentiation of chemotherapy medication (paclitaxel, vinblastine); observe patient.
Balch, P. A., & Bell, S. J. (2012). Prescription for herbal healing (2nd ed.). New York, N.Y.: Avery.
- Bone, K. (2003). A clinical guide to blending liquid herbs: herbal formulations for the individual patient. St. Louis, MI: Churchill Livingstone.
- Herbalpedia (2013)
- Mars, B. (2007). The desktop guide to herbal medicine: the ultimate multidisciplinary reference to the amazing realm of healing plants, in a quick-study, one-stop guide. Laguna Beach, CA: Basic Health Pub.
- Mills, S., & Bone, K. (2000). Principles and practice of phytotherapy: modern herbal medicine. Edinburgh; London: Churchill Livingstone.
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