Licorice is a perennial legume native to the Mediterranean region and southwest Asia and cultivated throughout much of Europe, Asia, and the southwestern United States. The plant has an erect, striated stem, reaching up to one meter in height, bearing alternate, compound, pinnate leaves with four to eight pairs of smooth, dark green leaflets, two to five centimeters long. Licorice flowers in midsummer, with clusters of purple or yellowish-white flowers which are followed by small, one-celled pods containing one to six kidney-shaped seeds. The root of the plant, which may reach up to 1 1/2 meters in length, is used medicinally and as a flavoring agent for foods, confections, drugs, and tobacco.
Licorice root contains a saponin glycoside compound called glycyrrhizin (also known as glycyrrhizic acid), which is considered the most active ingredient. Chemical analysis of licorice root has revealed 15 distinct saponins and at least 49 flavonoids.
The daily dosage approved by Commission E is 5 to 15 grams of whole root or preparations supplying 200 to 600 mg of glycyrrhizin. For deglycyrrhized licorice extracts (DGL), a common recommendation is two to four 380 mg chewable tablets 20 minutes before meals. Because excessive consumption of glycyrrhizin can cause potassium depletion, licorice root is not recommended for people taking digitalis or anyone with hypertension or kidney disease. Licorice root should not be used during pregnancy or by people with liver cirrhosis or cholestatic liver disorders.