Licorice (Glycyrrhiza glabra L.) and DGL (deglycyrrhizinated licorice)


The medicinally used part of licorice is the root and dried rhizome of the low-growing shrub Glycyrrhiza glabra. Currently, most licorice is produced in Greece, Turkey, and Asia.
Licorice has been used in ancient Greece, China, and Egypt, primarily for gastritis (inflammation of the stomach) and ailments of the upper respiratory tract. Ancient Egyptians prepared a licorice drink for ritual use to honor spirits of the pharaohs. Its use became widespread in Europe and Asia for numerous indications.
In addition to its medicinal uses, licorice has been used as a flavoring agent, valued for sweetness (glycyrrhizin, a component of licorice, is 50 times sweeter than table sugar). The generic name "glycyrrhiza" stems from ancient Greek, meaning "sweet root." It was originally used as flavoring for licorice candies, although most licorice candy is now flavored with anise oil. Licorice is still used in sub-therapeutic doses as a sweetening agent in herbal medicines, lozenges, and tobacco products (doses low enough that significant adverse effects are unlikely).
Licorice has a long history of medicinal use in Europe and Asia. At high doses, there are potentially severe side effects, including hypertension (high blood pressure), hypokalemia (low blood potassium levels), and fluid retention. Most adverse effects have been attributed to the chemical component glycyrrhizin, which is also known as glycyrrhizic acid or glycyrrhizinic acid. Licorice can be processed to remove the glycyrrhizic acid, resulting in DGL (deglycyrrhizinated licorice), which does not appear to share the metabolic disadvantages of licorice.

Related Terms

Alcacuz (Portuguese), alcazuz (Spanish), asam boi, bois doux (French), carbenoxolone, Chinese licorice, deglycyrrhizinised liquorice, deglycyrrhizinized succus Liquiritiae, duogastrone, Fabaceae (family), gan cao, gan zao, glabrene, glabridin, glucoliquiritin, glycyrrhetenic acid, Glycyrrhiza, Glycyrrhiza glabra, Glycyrrhiza uralensis Fisher, glycyrrhizin, isoflavan, isoliquiritigenin, kanzo (Japanese), LA, Lakrids (Danish), lakritze, Lakritzenwurzel (German), Leguminoseae (family), licochalcone-A, licorice root, Liquiritiae radix, Liquiritia officinalis, liquirizia (Italian), liquorice, orozuz, phytoestrogen, Persian licorice, prenyllicoflavone, radix glycyrrhizae, réglisse (French), regliz, Russian licorice, Shakuyanu-kanzo-tou, shao-yao-gan-cao-tang, STW 5-11 (extracts from bitter candy tuft, matricaria flower, peppermint leaves, caraway, licorice root, and lemon balm), Suβholzwurzel, sweet root, sweet wood, yashimadhu (Sanskrit), Yo Jyo Hen Shi Ko (Japanese).

evidence table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Adrenal insufficiency (Addison's disease) (Grade: C)
Addison's disease is a relatively common disorder to endocrinologists, but is rare and potentially fatal when presenting acutely. Treatment now involves replacement of glucocorticoids and mineralocorticoids with synthetic compounds, although historically patients took common salt and plant-based preparations, including licorice.
Aplastic anemia (Grade: C)
Limited study suggests that licorice may be beneficial in aplastic anemia, but results are inconclusive.
Apthous ulcers / canker sores (Grade: C)
Some research suggests that licorice extracts, DGL, and the drug carbenoxolone, may provide benefits for treating cankers sores. However, studies have been small with flaws in their designs. The safety of DGL makes it an attractive therapy if it does speed healing of these sores, but it is not clear at this time whether there is truly any benefit.
Atopic dermatitis (Grade: C)
Topical licorice extract gel has been shown to be effective in the treatment of atopic dermatitis in preliminary human study. Further research is needed to confirm these results.
Bleeding stomach ulcers caused by aspirin (Grade: C)
Although there has been some study of DGL in this area, it is not clear what effects DGL has on gastrointestinal bleeding.
Dental hygiene (Grade: C)
Further studies are needed prior to recommending for or against the use of glycyrrhizin in dental hygiene.
Familial Mediterranean fever (FMF) (Grade: C)
Early study of a multi-ingredient preparation containing licorice, called Immunoguard™, suggests possible effects in managing FMF. Well-designed study of licorice alone is necessary before a recommendation can be made.
Functional dyspepsia (Grade: C)
Early studies indicate that the herbal preparation STW 5, which contains licorice among many other herbal extracts, may help improve symptoms in patients with functional dyspepsia.
Herpes simplex virus (Grade: C)
Laboratory studies have found that DGL may hinder the spread and infection of herpes simplex virus. Studies in humans have been small, but they suggest that topical application of carbenoxolone cream may improve healing and prevent recurrence.
High potassium levels resulting from abnormally low aldosterone levels (Grade: C)
In theory, because of the known effects of licorice, there may be some benefits of licorice for high potassium levels caused by a condition called hypoaldosteronism. There is early evidence in humans in support of this use. However, research is preliminary and a qualified health care provider should supervise treatment.
HIV (Grade: C)
Early studies suggest that glycyrrhizin may inhibit HIV replication in patients with AIDS. However, human reports are lacking. Additional study is needed to make a firm recommendation.
Hyperprolactinemia (neuroleptic-induced) (Grade: C)
Shakuyaku-kanzo-to, an herbal medicine containing licorice, has been used for neuroleptic-induced hyperprolactinemia. However, additional studies are needed in this area.
Idiopathic thrombocytopenic purpura (Grade: C)
Early study has suggested that recombinant roasted licorice decoction combined with low-dose glucocorticoids may be more effective than glucocorticoids alone in treating idiopathic thrombocytopenic purpura. This combination has also shown a lower adverse effect rate than glucocorticoids alone.
Inflammation (Grade: C)
Many medical conditions are marked by inflammation. Because licorice can affect the metabolism of steroids, licorice is sometimes used to help decrease inflammation. Additional study is needed to make a firm recommendation.
Polycystic ovarian syndrome (Grade: C)
Spironolactone is a synthetic steroid that is commonly used as a diuretic in women with polycystic ovary syndrome. Licorice has been used in combination with spironolactone to reduce side effects related to the diuretic activity of spironolactone.
Reducing body fat mass (Grade: C)
Preliminary data shows that licorice may reduce body fat mass. Further research is needed to confirm these results.
Upper respiratory tract infections (common cold) (Grade: C)
Historically, licorice has been used for its expectorant and anti-tussive effects. The herbal combination product, KanJang®, has been studied for the treatment of uncomplicated upper respiratory tract infections. Results are mixed, and additional study is needed.
Viral hepatitis (Grade: C)
The licorice extracts DGL and carbenoxolone have been proposed as possible therapies for viral hepatitis. Further research is needed before a recommendation can be made.
Peptic ulcer disease (Grade: D)
Licorice extracts, DGL and carbenoxolone, have been studied for treating peptic ulcers. DGL (but not carbenoxolone) may offer some benefits. However, most studies are poorly designed and some results conflict. Therefore, it is unclear whether there is any benefit from licorice for this condition.