Licorice root (Liquiritiae radix)

Published May 15, 1985; Revised March 13, 1990; April 19, 1991, and September 21, 1991.
List of German Commission E Monographs (Phytotherapy)

Süßholzwurzel

Name of Drug

Liquiritiae radix, licorice root.

Composition of Drug

Licorice root consists of unpeeled, dried roots and stolons of Glycyrrhiza glabra L. [Fam. Fabaceae], as well as their preparations in effective dosage. The unpeeled roots contain at least 4 percent glycyrrhizic acid and 25 percent water-soluble matter. Licorice root also consists of peeled, dried roots and stolons of G. glabra L. [Fam. Fabaceae], as well as their preparations in effective dosage. The peeled roots contain at least 20 percent water-soluble matter.

The root contains several flavonoids of flavanone and isoflavanone derivatives in addition to the potassium and calcium salts of the glycyrrhizic acid. It also contains phytosterols and coumarins.

Uses

For catarrhs of the upper respiratory tract and gastric/duodenal ulcers.

Contraindications

Cholestatic liver disorders, liver cirrhosis, hypertonia, hypokalemia, severe kidney insufficiency, pregnancy.

Side Effects

On prolonged use and with higher doses, mineralocorticoid effects may occur in the form of sodium and water retention and potassium loss, accompanied by hypertension, edema, and hypokalemia, and, in rare cases, myoglobinuria.

Interactions with Other Drugs

Potassium loss due to other drugs, e.g., thiazide diuretics, can be increased. With potassium loss, sensitivity to digitalis glycosides increases.

Dosage

Unless otherwise prescribed:

Average daily dosage:

About 5 - 15 g of root, equivalent to 200 - 600 mg of glycyrrhizin; As Succus liquiritiae:

0.5 - 1 g for catarrhs of the upper respiratory tract, 1.5 - 3 g for gastric/duodenal ulcers; equivalent preparations. Mode of Administration Powdered root, finely cut root or dry extracts for infusions, decoctions, liquid or solid dosage forms for internal use (Succus liquiritiae).

Duration of Administration

Not longer than 4 - 6 weeks without medical advice. There is no objection to using licorice root as a flavoring agent up to a maximum daily dosage equivalent to 100 mg glycyrrhizin.

Actions

According to controlled clinical studies, glycyrrhizic acid and the aglycone of glycyrrhizic acid accelerate the healing of gastric ulcers. Secretolytic and expectorant effects have been confirmed in tests on rabbits. In the isolated rabbit ileum, an antispasmodic action has been observed at concentrations of 1:2500 - 1:5000.