# Plant Monograph: Licorice
**Name of plant:**
Licorice
**Catch phrase (Carmina Gadelica or traditional invocation if available):**
No specific invocation to licorice is recorded in the *Carmina Gadelica*. No historically attested Gaelic blessing specifically associated with *Glycyrrhiza glabra* is known. Its botanical name derives from Greek *glykys* (“sweet”) and *rhiza* (“root”), giving a fitting traditional epithet: **“the sweet root.”**
**Family:**
Fabaceae — the legume or pea family
**Genus and species:**
*Glycyrrhiza glabra* L.
**Other names:**
Licorice; Liquorice; Liquorice root; Sweet root; Sweetwood; Spanish liquorice; European liquorice; Common liquorice; *Glycyrrhiza*; Réglisse; Réglisse glabre; Lakrits; Süßholz. The genus name *Glycyrrhiza* literally refers to the plant's sweet root.
**Brief introduction:**
Licorice is a long-lived herbaceous perennial native to southern Europe, the Mediterranean region, western and central Asia and parts of the Middle East. It develops a deep, extensive root system and produces erect stems bearing pinnate leaves and small pale blue to violet flowers. The medicinally important root and underground stolons contain **glycyrrhizin**, a triterpenoid saponin responsible for much of the root's characteristic sweetness.
Licorice is one of the oldest continuously used medicinal plants in the world. Its history extends through ancient Egyptian, Greek, Roman, Persian, Chinese and Islamic medical traditions. It has traditionally been used particularly for **coughs, sore throats, respiratory irritation, digestive complaints and inflammatory conditions**.
Licorice is unusual among medicinal herbs because its principal active constituent can produce clinically significant physiological effects. The distinction between **deglycyrrhizinated licorice (DGL)** and ordinary glycyrrhizin-containing licorice is therefore particularly important in modern herbal practice.
**Traditional uses:**
* As a soothing remedy for coughs, hoarseness and irritated throats.
* As an expectorant and demulcent for respiratory complaints.
* For stomach discomfort, dyspepsia and irritation of the digestive tract.
* As a general anti-inflammatory and soothing medicinal root.
* As a sweetening and flavouring agent in compound herbal medicines.
**Historical use:**
* Ancient Egyptian physicians used licorice medicinally, and licorice root has been identified among materials associated with Egyptian burials.
* Greek physicians, including Dioscorides, described licorice as a medicinal root for throat and respiratory complaints and digestive conditions.
* Roman medical writers adopted Greek knowledge of the plant, and licorice became an established ingredient in European materia medica.
* Persian and later Islamic medical traditions employed licorice for respiratory, gastrointestinal and inflammatory complaints.
* Traditional Chinese medicine has used *Glycyrrhiza* species for centuries, particularly as a harmonizing ingredient in complex formulas; however, Chinese licorice species and European *G. glabra* should not automatically be considered chemically identical.
**Parts used and method of use:**
* Root.
* Rhizomes and underground stolons.
Used as:
* Decoction or medicinal tea.
* Powdered root.
* Fluid or dry extract.
* Deglycyrrhizinated licorice (DGL) preparations, particularly for digestive applications.
**Use in healing (modern herbal practice):**
* Symptomatic relief of cough and throat irritation.
* As a demulcent for irritated mucous membranes.
* Traditional treatment of dyspeptic and gastrointestinal discomfort.
* DGL preparations are used as complementary support for upper gastrointestinal symptoms.
* Investigated for anti-inflammatory, antimicrobial, antioxidant and hepatoprotective activity.
Licorice has substantially more pharmacological and clinical research than many traditional herbs, but its usefulness must be balanced against the **well-established toxicity of excessive glycyrrhizin exposure**.
**Pharmacology and biochemistry:**
* **Glycyrrhizin (glycyrrhizic acid)** — a triterpenoid saponin and the principal sweet compound responsible for many systemic effects.
* **Glycyrrhetinic acid** — the active aglycone produced from glycyrrhizin and an important mediator of licorice's mineralocorticoid-like effects.
* **Flavonoids**, including liquiritin, liquiritigenin, isoliquiritigenin and glabridin.
Mechanisms:
* Glycyrrhetinic acid inhibits **11β-hydroxysteroid dehydrogenase type 2**, reducing conversion of cortisol to cortisone and allowing cortisol to stimulate mineralocorticoid receptors.
* This can produce **sodium and water retention with potassium loss**, explaining licorice-induced hypertension and hypokalemia at excessive exposure.
* Flavonoids and other constituents demonstrate antioxidant, anti-inflammatory, antimicrobial and other pharmacological effects in experimental systems.
**Overall profile:**
Licorice is a **demulcent, expectorant, anti-inflammatory and flavouring herb with significant systemic pharmacology**. Its therapeutic usefulness is genuine but accompanied by an important safety limitation: ordinary glycyrrhizin-containing licorice can cause **pseudoaldosteronism**, particularly when consumed in substantial quantities or for prolonged periods. DGL removes most glycyrrhizin and therefore has a substantially different safety and pharmacological profile.
**Common dosage:**
* **Dried root/decoction:** approximately 1.5–4.5 g dried root daily, divided into preparations according to traditional European herbal practice.
* **Powdered root:** approximately 1–4 g daily, depending upon preparation and indication.
* **Fluid extract:** approximately 2–4 mL per day of an appropriately standardized preparation.
* **DGL:** commonly 380–760 mg of chewable DGL extract before meals, with product-specific dosing preferred because glycyrrhizin removal and extract concentration vary considerably.
For glycyrrhizin-containing preparations, duration matters as much as dose. Licorice should **not** be treated as an innocuous everyday sweetener when medicinal quantities are consumed.
**Safety factors (including side effects):**
* Prolonged or excessive intake of glycyrrhizin-containing licorice can cause **hypertension, edema, sodium retention and potassium depletion**.
* Hypokalemia can become severe enough to cause muscle weakness, abnormal heart rhythms and, in extreme cases, serious cardiac complications.
* Licorice should be avoided or used only under medical supervision by people with hypertension, cardiovascular disease, kidney disease, liver disease or disorders involving electrolyte balance.
* Pregnancy and breastfeeding require particular caution; medicinal doses of glycyrrhizin-containing licorice should generally be avoided during pregnancy.
* Long-term daily use of conventional licorice is inappropriate without professional supervision; DGL is not equivalent to ordinary licorice because most glycyrrhizin has been removed.
**First aid / adverse reaction response:**
* **Mild edema, headache or elevated blood pressure after prolonged use:** discontinue glycyrrhizin-containing licorice and seek medical advice.
* **Muscle weakness, cramping or unusual fatigue:** discontinue use and seek prompt medical assessment because these may indicate significant potassium depletion.
* **Palpitations, irregular heartbeat, severe weakness or fainting:** seek **urgent/emergency medical attention**, as severe hypokalemia can produce dangerous arrhythmias.
* **Suspected overdose or significant adverse reaction:** stop the product and contact a poison-control centre or emergency medical service; bring the product packaging to identify the preparation and concentration.
**Drug interactions:**
* **Diuretics, particularly potassium-losing diuretics:** licorice can worsen potassium depletion and electrolyte disturbances.
* **Digoxin and related cardiac glycosides:** hypokalemia caused by licorice can increase the risk of digoxin toxicity and arrhythmias.
* **Corticosteroids:** licorice may enhance mineralocorticoid effects and contribute to fluid retention and potassium loss.
* **General interaction considerations:** licorice may interfere with medicines affecting blood pressure, electrolytes and cardiac rhythm; people taking such medications should avoid medicinal doses of glycyrrhizin-containing licorice unless supervised by a clinician or pharmacist.
**Horticultural requirements:**
* USDA / Canadian zone: **USDA Zones 5–9**, although hardiness varies with cultivar and winter conditions.
* Soil pH: **approximately 6.0–8.0**, with fertile, reasonably deep soil preferred.
* Light requirements: **Full sun**.
* Moisture: **Moderately moist to moist**, but well drained; the plant appreciates consistent moisture during active growth.
* Other notes (growth habit, harvest timing, etc.):
* **Growth habit:** Herbaceous perennial reaching approximately 1–1.5 m in height, spreading through an extensive network of rhizomes and stolons.
* **Flowering/fruiting:** Pale blue, lilac or violet pea-like flowers occur in summer, followed by small leguminous seed pods.
* **Harvest timing:** Medicinal roots are generally harvested from mature plants in autumn, after the aerial portions have died back; commercially cultivated plants are often harvested after several years of growth to obtain substantial roots.
* **Habitat:** Naturally occurs in relatively warm temperate and Mediterranean regions, often in deep, fertile soils and areas with adequate moisture.
* **Propagation/cultivation notes:** Propagation is commonly accomplished by division of rhizomes or root cuttings. Seed germination can be slow or unreliable. Licorice spreads aggressively through underground rhizomes and should be planted where its expansion can be controlled. Deep, fertile soil is particularly important because the medicinal root system becomes extensive.
**Sampling of clinical reports / studies:**
* **Peptic-ulcer/dyspepsia research:** DGL preparations have been investigated for upper gastrointestinal symptoms and ulcer-related conditions, with some encouraging findings, although clinical studies vary in formulation and quality.
* **Pharmacological research:** Glycyrrhizin and glycyrrhetinic acid have demonstrated anti-inflammatory, antiviral, antioxidant and hepatoprotective effects in experimental models; these findings should not automatically be interpreted as evidence that licorice treats corresponding human diseases.
* **Phytochemical research:** The chemistry of *Glycyrrhiza* is particularly well characterized, with glycyrrhizin, glycyrrhetinic acid, flavonoids and numerous other constituents contributing to its pharmacological activity.
* **Ethnobotanical evidence:** Licorice has an exceptionally long and geographically broad medicinal history, spanning ancient Egypt and Greece, the Mediterranean, Persia, Islamic medicine, Europe and East Asian medical traditions.
* **Overall assessment of evidence:** **Strong historical and ethnobotanical evidence; extensive pharmacological research; moderate but indication-dependent clinical evidence.** Licorice has genuine medicinal value, particularly as a demulcent and in selected gastrointestinal and respiratory applications, but its systemic effects make safety and duration of use unusually important.
**Important distinction for the monograph collection:**
Licorice is one of the herbs where the old apothecary principle **“the dose makes the poison”** is particularly literal. Ordinary licorice root contains glycyrrhizin and can produce clinically significant electrolyte and cardiovascular effects when consumed excessively or continuously. **DGL is a fundamentally different preparation**: removing most glycyrrhizin preserves many of the root's locally acting constituents while greatly reducing the mechanism responsible for pseudoaldosteronism. This distinction should remain prominent wherever licorice appears in the collection.
Educational Use Only: The information presented on this page is provided for educational, historical, and informational purposes only. ArdNemeton na Tuatha and Bhùth Draoi do not provide medical advice. Always consult your physician and pharmacist before using any herb, mushroom, supplement, or botanical product for medicinal purposes. Traditional uses described herein do not constitute medical claims.