Licorice is traditionally used to sooth coughs and the skin. People also take licorice for inflammation, bronchitis, arthritis, and constipation. Health care providers, such as naturopaths, may prescribe licorice root products for peptic ulcer, chronic gastritis, and for primary adrenocortical insufficiency.
Almost 8 of the licorice plant is composed of a glycoside called glycyrrhizin. Glycosides are chemical compounds that could possibly have many positive effects in the body. Glycyrrhizin specifically reduces the activity of two enzymes that break down prostaglandin E (PGE). Lower than normal levels of PGE have been associated with stomach disorders including colic, stomach inflammation, and ulcers. By inhibiting the body's disposal of PGE, glycyrrhizin allows more PGE to circulate in the body which is believed to promote the production of stomach mucus, whereby decreasing the production of painful and potentially dangerous stomach acids that lead to many stomach conditions. Both effects help to protect stomach tissue; consequently, true licorice has been used in connection with ulcers and other stomach conditions. Glycyrrhizin also promotes the production of mucus in the respiratory tract. This increase may make the respiratory tract mucus less sticky and may also promote its removal from the body. Additionally, very sweet substances such as licorice are known to enhance the elimination of mucus from the lungs. Therefore, true licorice has been used with severe respiratory conditions such as bronchitis. It may also be used to soothe a sore throat and to relieve coughing. Some licorice compounds may be found in cough syrups and cough lozenges as a cough suppressant, as well as a flavoring.
Licorice has also been used in Traditional Chinese Medicine (TCM) to treat conditions ranging from diabetes to tuberculosis. The two major constituents of licorice, glycyrrhizin and flavonoids, may also exhibit anti-inflammatory effects and inhibit the breakdown of the cortisol produced by the body. Licorice may also have antiviral properties, although this has not been proven in human pharmacological studies. In test tube studies, the flavonoids of the licorice plant have been shown to kill Helicobacter pylori, the bacteria causing most ulcers and stomach inflammation.
An extract of licorice, called liquiritin, has been used in connection with melasma, a pigmentation disorder of the skin. However, the usefulness of licorice for treating this condition has not been substantiated.
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Dosage and Administration
Licorice can be taken in the following forms:
- Dried root: 1 to 5 g three times per day as decoction
- Tincture: 2 to 4 mL three times per day
- DGL extract: 0.4 to 1.6 g three times per day for peptic ulcer; in chewable tablet form 300 to 400 mg 20 minutes before meals for peptic ulcer
For sore throat treatment in older children, a piece of licorice root may be chewed or licorice tea may be used. The appropriate dose of tea for a child should be determined by adjusting the recommended adult dose to account for the child's weight. Most herbal dosages for adults are calculated on the basis of a 150 lb (70 kg) adult. Therefore, if the child weighs 50 lb (20-25 kg), the appropriate dose of licorice for this child would be 1/3 of the adult dosage.
You should be very careful if you are taking large amounts of licorice products or if you chew licorice-flavored tobacco or use other licorice-flavored products. If so, you are at risk for licorice side effects and toxicities.