Chinese Name : 甘草
Latin Name : Radix Glycyrrhizae
This herb is the root and rhizome of Glycyrrhiza uralensis Fisch., G. inflata Bat., or G. glabra L. of the Leguminosae family. Grown in Inner Magnolia and the Gansu, Shanxi, and Xinjiang provinces of China, it is also found throughout all regions of Europe, the Middle East, and Central Asia. It is harvested in spring and autumn, sliced after removal of the residual stem and rootlets, dried in the sun, and used unprocessed or stir baked with honey.
Licorice root is highly prized in TCM and is widely prescribed. Next to ginseng in importance, it is a great corrective adjunct and harmonizing ingredient in a large number of recipes. Dry licorice root is an antipyretic, good for detoxification and pain relief, and an antitussive and expectorant. Honey-processed licorice root is good for replenishing Qi, invigorating the spleen, and preventing irregular heartbeats. Licorice root is an excellent antiaging herb.
Use of Licorice Root in TCM
Sweet in taste and neutral, licorice root acts on the heart, lung, spleen, and stomach meridians.
Effects, Medicinal Uses, and Combinations
- Replenishes Spleen-Qi and Stomach-Qi : for a deficiency of Spleen-Qi and Stomach-Qi manifested as indigestion, chronic gastroenteritis, poor appetite, chronic dysentery, and anemia, licorice root is often combined with poria, codonopsis root (dang shen), and white atractylodes rhizome, as in Si Jun Zi Tang (R2).
- Eliminates coughs and phlegm, relieves Heat, and detoxifies :
- To treat Wind-Heat type colds and coughs, licorice root is used with platycodon root (jie geng), arctium fruit, peucedanum root, and mulberry leaf.
- To treat Wind-Cold types of colds and coughs, licorice root is blended with ephedra and bitter apricot kernel.
- For coughs due to an accumulation of Heat in the lungs, licorice root is mixed with unprocessed gypsum, ephedra, and bitter apricot kernel.
- Detoxifies and removes pathogenic Heat and toxins : for detoxification, sores, ulcers, pyogenic skin infections, and sore throats, licorice root is dispensed with lonicera and forsythia fruit in a decoction. It can be blended with platycodon for a swollen throat, or with mungbean or siler (fang feng) for food positioning.
- Relieves spasms and pain : for intestinal cramps and stomach pain, it is mixed with cinnamon twig and white peony root in a decoction.
In a decoction of 3 to 9 g, or 10 to 30 g for detoxification. To reduce heat and to detoxify, use dried licorice root. For all other conditions, use processed licorice root.
- If taken for a long period of time or overdosed, it may caused edema or hypertension.
- Anyone with a history of cardiovascular disorders, kidney disorders, low blood potassium count, high blood pressure, diabetes, or women who are pregnant or breast feeding should avoid licorice root or take with caution.
Side Effects and Toxicity
At the normal recommended dose, this herb is safe. However, continuous use or an overdose can result in sodium retention, lower the basal metabolic rate, and decrease thyroid function, causing edema and hypertension.
The MLD of glycyrrhizin in mice by subcutaneous administration was 1 g/kg. The LD50 of glycyrrhizic acid (GA) in mice by intraperitoneal administration was 308 mg/kg.
Licorice root contains about 1 to 24 percent of triterpene glycoside glycyrrhizin, which is the calcium or potassium salt of glycyrrhizic acid. Other contents include flavonoids, isoflavonoids, chalcones, coumarin, triterpenoids, isoliquiritigenin, licobenzoburan, liquirigenin, liquirin, mannite, betulic acid, biotin, sterols, starch, volatile oil, sugar, lignin, amino acids, amines, gum, and wax.
- Antiulcer and spasmolytic effects. The fluid extract of licorice root :
- Relieves the spasm of the gastrointestinal smooth muscles ;
- Inhibits the secretion of gastric acid and reduces the activity by direct absoption of the acid, and
- Is therapeutic and protective as shown by experimental ulceration of the gastrointestinal mucous surface of rats.
- Detoxication through absorption, neutralization, and combination of toxins.
- Licorice root decoction decreases or detoxifies toxins from food, drugs, bacteria, and metabolites.
- It reduces the toxicity from strychnine, histamine, chlorohydrate, benzene, arsenic, barbitol, tetanus toxin, and diphtheria toxin.
- It increases detoxication in the liver.
- Liver protection. Licorice root provided protection for rats’ livers against carbontetrachloride and promoted the regeneration of liver cells.
- Glycyrrhizin has shown adrenocortical hormone action, mineral corticoid action with fluid, and sodium retention and potassium loss in urine, leading to hypertension.
Licorice root extract is widely used in China for gastric ulcers, duodenal ulcers, bronchial asthma, infectious hepatitis, malaria, diabetes insipidus, and contact dermatitis. The flavonoid extracts have recently been shown to be strongly antioxidant and antihepatotoxic.