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Botanical name

Liquorice - Glycyrrhiza glabra L.


Legume/Pea family (Fabaceae)

Useful information about the plant

Liquorice populates a large area with its various different varieties from southeastern Europe to Asia, Ukraine, Central Russia, Southern Siberia, Afghanistan to western China. The plant is farmed in warm-temperate to subtropical countries on all continents. The durable bush that grows to over 1m high is anchored with a long, thick taproot and thick lateral roots in the soil. Each year strong stems with odd pinnate leaves (each from 3 to 7 pairs) grow from a very woody rhizome (underground stem). The individual leaflets are ovate and abaxial, hairy underneath, otherwise glabrous (Latin "glaber", "glabra" = bald). Lots of small pale lilac-coloured butterfly flowers grow close together in 10 to 15cm long racemes in the leaf axils. The fruits are 1.5 to 2.5cm long husks with kidney-shaped seeds.
The name genus Glycyrrhiza from the Greek "glykys" = sweet and 'rhiza' = root refers to the very sweet-tasting root, caused by the glycyrrhizin contained in the root, a triterpenoid, which has approximately 50 times the sweetening power of cane sugar (sucrose). A "liquorice juice" (Liquiritiae succus) is taken from the root, which is incorporated into the world's most popular liquorice sweets. To do this, the fresh roots are crushed and boiled with water for many hours. The extracted juice is very slowly thickened into a viscous consistency. The typical liquorice flavour forms during this process. The viscous extract is incorporated at a maximum of 5% to 50% into liquorice products. These are made from sugar, flour, starch and/or gelatin, as well as fragrances and flavours. The Federal Association of the Confectionery Industry specifies a maximum level of 200mg of glycyrrhizin per 100g of liquorice products. Products with a higher content must be labeled as "Strong liquorice", indicating a high intake (see side effects). The first liquorice in the typical worm shape is said to have been on a German conveyor belt in 1925.

Medicinally used plant parts (drug)

The dried, peeled or unpeeled roots are used. The commercial drug comes from farms in China, Russia and Turkey, also from Italy, Bulgaria and Spain.

Ingredients of the drug

Liquorice root contains triterpenoid (mainly glycyrrhizin), flavonoids, isoflavones and polysaccharides.

Descriptions of the quality

The quality of the following drugs or drug preparations is specified in the European Pharmacopoeia (Ph. Eur.):

  • Liquorice root (Liquiritiae radix)
  • Set, liquorice root ethanolic fluid extract (Liquiritiae extractum fluidum ethanolicum normatum)
  • Liquorice root dry extract as a flavouring (Liquiritiae extractum siccum ad saporandum)
The quality of set liquorice dry extract (Liquiritiae extractum siccum normatum) is specified in the German Drug Codex (DAC).

Medical Application

Recognised medical use

With catarrh in the upper respiratory tract and Ulcus ventriculi/ duodeni (gastric and duodenal ulcers (Commission E); as adjunctive therapy in gastric and duodenal ulcers and gastritis; as a decongestant in cough and bronchitis (ESCOP).

Traditional use

Liquorice root is traditionally used as a mild-acting drug for heartburn and acid-related stomach pains as well as in combination with other drugs to help relieve the mucus in the respiratory tract (traditional use in accordance with § 109a).

Medicinal herbal preparations in finished drug products

  • Cut liquorice root to prepare tea
  • Dried extract in soluble instant teas and chewable tablets
  • Alcoholic extracts in drops


Prepared drugs: see package insert;
Tea infusion: take 1 cup of liquorice tea 3 to 4 times a day, daily dose: 5 to 15g of the drug equivalent to 200 to 600mg of glycyrrhizin.

Preparation of a tea infusion

Mix 1 to 1.5g of finely chopped or coarsely powdered liquorice root with 150ml of cold water, boil, then remove from the hob and strain after 10 to 15 minutes. The infusion can also be made with boiling water.


Liquorice root should not be taken by people who have cholestatic liver diseases, liver cirrhosis, high blood pressure, potassium deficiency, severe renal insufficiency. Even during pregnancy liquorice root and liquorice should be avoided.

Side effects

With prolonged use and higher doses, mineralocorticoid effects in the form of a sodium and water retention can cause potassium loss with high blood pressure, oedema (accumulation of fluid in tissues) and in rare cases, myoglobinuria (muscle tissue protein in the urine).


Potassium deficiency cause by other drugs (e.g. thiazide and loop diuretics) can be increased; with reduced potassium levels, the sensitivity to cardiac glycosides (digitalis) increases.


Drug monographs

Commission E, ESCOP, WHO (Vol. 1)

Further reading

Wichtl: Teedrogen und Phytopharmaka, pg. 397
Schilcher: Leitfaden Phytotherapie, pg. 251
Van Wyk: Handbuch der Arzneipflanzen, pg. 160
Kommentar zum Europäischen Arzneibuch (Liquorice root, no. 0277; Liquorice root fluid extract, 1536; Liquorice root extract as a flavouring, 2378)

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