Herb to Know: Licorice


Photograph by Jerry Pavia

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• Glycyrrhiza glabra
• (Gliss-ih-RY-zuh GLAY-bruh)
• Family Leguminosae
• Tender perennial.

Things are seldom what they seem.” Is it a sign of the times that in the United States today, much commercial licorice candy contains no licorice at all but instead gets its flavor from anise oil? Licorice root itself has a musky flavor and is fifty times as sweet as table sugar. Most licorice root imported into the United States goes into flavoring tobacco.

The genus Glycyrrhiza (from Greek words meaning “sweet root”) comprises about twenty species of sticky, sometimes hairy perennial herbs with creeping rhizomes, compound leaves, pealike flowers, and leathery or prickly inflated pods. It is native to Eurasia, Australia, and North and South America.

G. glabra is native to dry scrubland or damp ditches in the Mediterranean region and southwestern Asia. It was introduced into England by Dominican friars about 500 years ago and is cultivated in Russia, Greece, Spain, the Middle East, Italy, India, California, and Arizona. It is hardy in Zones 7 to 9.

Plants stand 3 to 5 feet tall and have pinnately compound leaves of nine to seventeen 1- to 2-inch elliptical leaflets. The stem and leaf stalks are fuzzy. Short, stalked spikes of blue or violet flowers in the leaf axils bloom in late summer. The individual flowers are about 1/2 inch long and are followed by smooth, oblong pods 1/2 to 1 inch long containing two to four seeds. (Glabra, Latin for “smooth”, refers to the pod.)

Medicinal Uses For Licorice

Licorice has been used in medicine since antiquity. The Greek historian Theophrastus (372–286 b.c.) made the dubious claim that eating licorice root and mare’s milk cheese enabled the Scythians (an ancient nomadic people who lived near the Black Sea) to go eleven to twelve days without drinking. He also reported on the use of the root to treat respiratory disorders. The Chinese have used the roots of G. glabra and G. uralensis to treat a wide range of illnesses; they include licorice in many of their formulations, believing that it reduces the toxicity of certain other ingredients (they call it the Great Detoxifier). Native Americans and early white settlers used the native G. lepidota to bring on menstrual periods, expel the placenta following childbirth, and relieve earache, toothache, and fever. Licorice has also been used to treat sore throat, urinary tract infections, stomach ulcers, constipation, and Addison’s disease, a disorder marked by ­insuff­icient secretion of hormones of the adrenal cortex. Externally, it has been used to soothe irritated skin and eyes.

Scientific studies support many of these uses. Research has shown licorice’s potential to relieve inflammation associated with arthritis, skin irritations, and respiratory conditions. Some studies have shown it to be as effective as hydrocortisone without the latter’s side effects. Other studies have shown that it protects the liver and keeps red blood cells from rupturing in the presence of certain toxins. It has been used successfully to help prevent adrenal gland atrophy in patients receiving conventional drug treatment for Addison’s disease. A study involving laboratory mice showed that components of licorice stimulated the production of interferon, a key chemical in the immune system. Many studies have shown licorice’s ability to inhibit the growth of bacteria, including drug-resistant strains, and viruses. Several plant estrogens have been isolated from it. One Japanese study showed that licorice stimulated normal ovulation in women with infrequent menstrual periods. It is a mild laxative, but when given with stronger laxatives, it makes them less irritating to the digestive tract. Derivatives of the root have been shown to be as effective as codeine in suppressing coughs.

The long-term use of licorice can result in sodium retention and potassium loss, and pregnant women, people who have high blood pressure or kidney disease, or those who are taking digitalis medications should not take it at all. Daniel B. Mowrey, author of The Scientific Validation of Herbal Medicine, maintains, however, that whole licorice roots or products made from them are not toxic and that nearly all recorded cases of licorice toxicity (including cardiac arrest) have involved taking concentrated root extracts or derivatives, such as carbenoxolone sodium, an ingredient in some ulcer remedies. All of these contain large amounts of glycyrrhizin, the cortisonelike component that is also responsible for licorice’s intense sweetness. He cites several studies showing that deglycyrrhizinated licorice (licorice treated to remove the glycyrrhizin) was effective in healing ulcers of the stomach and small intestine. It would make sense to consult a qualified health practitioner if you are considering taking licorice for its health benefits.

Other Uses For Licorice

Licorice flavors laxatives, soft drinks, ice cream, beer, liqueurs, mouthwash, toothpaste, and soy products, and it is a foaming agent in beers and fire extinguishers, and a spreading agent in insecticides. The pulp is used for fertilizer (like other legumes, the plants have the ability to fix nitrogen from the air) and to make composition board and insulation. Licorice is added to chocolate as a sugar extender and to cosmetics for its skin-soothing qualities.

Growing Licorice

Choose a spot in full sun or part shade. Licorice plants thrive in moist, fertile, but well-drained soil. They are easily grown from divisions or root cuttings planted 1 to 11/2 feet apart, or sow seeds outdoors in spring or fall. Commercial crops are harvested after three or four years’s growth, when the glyc­yrrhizin content is highest but before the plants bear fruit. Dig up the roots in the fall after the tops are dry and compost the tops. New plants will grow from any bits of root left in the soil, which may be a liability if you are trying to clear an area of licorice. Dry the roots for several months and then store them in a cool place.

In places where licorice doesn’t winter over, you can try growing it in a greenhouse in deep pots of well-drained sandy loam or grow it in the ground outside but dig the plants in the fall and winter them over in soil in a cool basement or root cellar.


• Logee’s Greenhouses, 141 North St., Danielson, CT 06239. Catalog $3. Plants.
• Richters, Goodwood, ON, Canada L0C 1A0. Catalog free. Seeds, plants, dried root.
• Sunnybrook Farms, PO Box 6, Chesterland, OH 44026. Catalog $2. Plants.