Liquorice or licorice (// LIK-(ə-)rish or // LIK-(ə-)ris) is the root of Glycyrrhiza glabra from which a somewhat sweet flavor can be extracted. The liquorice plant is a legume (related to beans and peas) that is native to southern Europe and parts of Asia. It is not botanically related to anise, star anise, or fennel, which are sources of similar flavouring compounds. The word 'liquorice'/'licorice' is derived (via the Old French licoresse), from the Greek γλυκύρριζα (glukurrhiza), meaning "sweet root", from γλυκύς (glukus), "sweet" + ῥίζα (rhiza), "root", the name provided by Dioscorides.
It is a herbaceous perennial, growing to 1 m in height, with pinnate leaves about 7–15 centimeters (3–6 in) long, with 9–17 leaflets. The flowers are 0.8–1.2 cm (½–⅓ in) long, purple to pale whitish blue, produced in a loose inflorescence. The fruit is an oblong pod, 2–3 centimetres (1 in) long, containing several seeds. The roots are stoloniferous. The scent of liquorice root comes from a complex and variable combination of compounds, of which anethole is at most a minor component (0-3% of total volatiles). Much of the sweetness in liquorice comes from glycyrrhizin, which has a sweet taste, 30–50 times the sweetness of sugar. The sweetness is much different than sugar, being less instant and lasting longer.
Cultivation and uses 
Liquorice extract is produced by boiling liquorice root and subsequently evaporating most of the water, and is traded both in solid and syrup form. Its active principle is glycyrrhizin, a sweetener between 30 to 50 times as sweet as sucrose, and which also has pharmaceutical effects.
Liquorice flavour is found in a wide variety of liquorice candies or sweets. In Britain and the US these are usually sweet. In most of these candies the taste is reinforced by aniseed oil, and the actual content of liquorice is very low. In continental Europe however, strong, salty candies are popular.
In the Netherlands, where liquorice candy ("drop") is one of the most popular forms of sweet, only a few of the many forms that are sold contain aniseed, although mixing it with mint, menthol or with laurel is quite popular. Mixing it with ammonium chloride ('salmiak') is also popular. The most popular liquorice, known in the Netherlands as zoute drop (salty liquorice) actually contains very little salt, i.e. sodium; the salty tast is probably due to ammonium chloride, and the blood pressure raising effect is due to glycyrrhizin, see below.
Pontefract in Yorkshire was the first place where liquorice mixed with sugar began to be used as a sweet in the same way it is in the modern day. Pontefract cakes were originally made there. In County Durham, Yorkshire and Lancashire it is colloquially known as Spanish, supposedly because Spanish monks grew liquorice root at Rievaulx Abbey near Thirsk.
Liquorice flavouring is also used in soft drinks, and in some herbal infusions where it provides a sweet aftertaste. The flavour is common in medicines to disguise unpleasant flavours.
Liquorice is popular in Italy (particularly in the South) and Spain in its natural form. The root of the plant is simply dug up, washed and chewed as a mouth freshener. Throughout Italy unsweetened liquorice is consumed in the form of small black pieces made only from 100% pure liquorice extract; the taste is bitter and intense. In Calabria a popular liqueur is made from pure liquorice extract. Liquorice is also very popular in Syria where it is sold as a drink. Dried liquorice root can be chewed as a sweet. Black liquorice contains approximately 100 calories per ounce (15 kJ/g).
It is also the main ingredient of a very well known soft drink in Egypt, called عرقسوس ('erk-soos).
Sticks of liquorice typically have a diameter between two and ten millimetres. Although they resemble plain wooden sticks, they are soft enough to be chewed on. They used to be popular among Dutch, Danish and Swedish children. In Lancashire and Yorkshire in the early 1950s & 1960s, wooden sticks of liquorice, around 8mm diameter, were readily available (and popular) in sweet shops. Also in Essex during late 50s. They were bought as 'sticks of liquorice', and they were chewed by young children. The wood was yellowish, and fibrous when chewed. Liquorice root can have either a salty or sweet taste. The thin sticks are usually quite salty and sometimes taste like salmiak (salty liquorice), whereas the thick sticks are usually quite sweet, with a salty undertone. Liquorice root is also widely available in Denmark. It is also sold by the drugstore and drysalter chain Matas and many greengrocers.
The compound glycyrrhizic acid, found in liquorice, is now routinely used throughout Japan for the treatment and control of chronic viral hepatitis, and there is a possible transaminase-lowering effect. Hepatoprotective mechanisms have been demonstrated in mice. Recent studies indicate that glycyrrhizic acid disrupts latent Kaposi's sarcoma (as also demonstrated with other herpesvirus infections in the active stage), exhibiting a strong anti-viral effect. The Chinese use liquorice to treat Tuberculosis 
Liquorice affects the body's endocrine system as it contains isoflavones (phytoestrogens). It might lower the amount of serum testosterone slightly, but whether it affects the amount of free testosterone is unclear. Consuming liquorice may prevent the development of hyperkalemia in persons on hemodialysis. Large doses of glycyrrhizinic acid and glycyrrhetinic acid in liquorice extract can lead to hypokalemia and serious increases in blood pressure, a syndrome known as apparent mineralocorticoid excess. These side effects stem from the inhibition of the enzyme 11β-hydroxysteroid dehydrogenase (type 2) and subsequent increase in activity of cortisol on the kidney. 11β-hydroxysteroid dehydrogenase normally inactivates cortisol in the kidney; thus, liquorice's inhibition of this enzyme makes the concentration of cortisol appear to increase. Cortisol acts at the same receptor as the hormone aldosterone in the kidney and the effects mimic aldosterone excess, although aldosterone remains low or normal during liquorice overdose. To decrease the chances of these serious side effects, deglycyrrhizinated liquorice preparations are available. The disabling of similar enzymes in the gut by glycyrrhizinic acid and glycyrrhetinic acid also causes increased mucus and decreased acid secretion. As it inhibits Helicobacter pylori, it is used as an aid for healing stomach and duodenal ulcers, and in moderate amounts may soothe an upset stomach. Liquorice can be used to treat ileitis, leaky gut syndrome, irritable bowel syndrome and Crohn's disease as it is antispasmodic in the bowels.
The compounded carbenoxolone is derived from liquorice. Some studies indicate that it inhibits 11β-Hydroxysteroid dehydrogenase type 1, an enzyme that is highly expressed in liver and fat tissues, where it plays a role in metabolism, and in the brain, where the same enzyme is involved in stress response that has been associated with age-related mental decline.
Alternative medicine 
In traditional Chinese medicine, liquorice (मुलेठी, 甘草) is commonly used in herbal formulae to "harmonize" the other ingredients in the formula and to carry the formula to the twelve "regular meridians" and to relieve a spasmodic cough.
In herbalism it is used in the Hoxsey anti-cancer formula, and is a considered adaptogen which helps reregulate the hypothalamic-pituitary-adrenal axis. It can also be used for auto-immune conditions including lupus, scleroderma, rheumatoid arthritis and animal dander allergies.
Glycyrrhizin from Glycyrrhiza root has been shown to modulate airway constriction, lung inflammation and infiltration of eosinophils in bronchial areas by stimulating CD4 and CD8 immune cell function.
More recently licorice has been used for symptomatic improvement in patients with the Postural Tachycardia Syndrome.
90% of liquorice is used in tobacco products. Liquorice adds a mellow, sweet woody flavour and enhances the taste of tobacco. The burning liquorice also generates some toxins found in the smoke, and the glycyrrhizin expands the airways, which allows users to inhale more smoke.
Excessive consumption of liquorice or liquorice candy is known to be toxic to the liver and cardiovascular system, and may produce hypertension (acquired pseudohyperaldosteronism) and edema. In occasional cases, blood pressure has increased with excessive consumption of liquorice tea, but such occasions are rare and reversible when the herb is withdrawn. Most cases of hypertension from liquorice were caused by eating too much concentrated liquorice candy. Doses as low as 50 grams (2 oz) of liquorice daily for two weeks can cause a significant rise in blood pressure.
The European Commission 2008 report suggested that "people should not consume any more than 100mg of glycyrrhizic acid a day, for it can raise blood pressure or cause muscle weakness, chronic fatigue, headaches or swelling, and lower testosterone levels in men." Haribo, manufacturer of Pontefract cakes, stated: "Haribo advises, as with any other food, liquorice products should be eaten in moderation." A 56-year-old Yorkshire woman was hospitalized after liquorice overdose (200 grams or 7 ounces a day), which caused muscle failure. The hospital restored her potassium levels, by intravenous drip and tablets, allowing her to recover after 4 days.
Comparative studies of pregnant women suggest that excessive amounts of liquorice (100g a week) may also adversely affect both IQ and behaviour traits of offspring.
- "Glycyrrhiza glabra information from NPGS/GRIN". www.ars-grin.gov. Retrieved 6 March 2008.
- licorice. Merriam-Webster's Medical Dictionary, © 2007 Merriam-Webster, Inc.
- γλυκύρριζα, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus
- γλυκύς, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus
- ῥίζα, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus<
- liquorice, on Oxford Dictionaries
- google books Maud Grieve, Manya Marshall - A modern herbal: the medicinal, culinary, cosmetic and economic properties, cultivation and folk-lore of herbs, grasses, fungi, shrubs, & trees with all their modern scientific uses, Volume 2 Dover Publications, 1982 & Pharmacist's Guide to Medicinal Herbs Arthur M. Presser Smart Publications, 1 Apr 2001 2012-05-19
- Huxley, A., ed. (1992). New RHS Dictionary of Gardening. ISBN 0-333-47494-5
- Brown, D., ed. (1995). "The RHS encyclopedia of herbs and their uses". ISBN 1-4053-0059-0
-  the online Dutch food composition database]
- "Right good food from the Ridings". AboutFood.com. 25 October 2007.
- "Where Liquorice Roots Go Deep". Northern Echo. Retrieved 9 December 2008.
- Licorice Calories
- Shibata, S (2000 Oct). "A drug over the millennia: pharmacognosy, chemistry, and pharmacology of licorice.". Yakugaku Zasshi 120 (10): 849–62. PMID 11082698.
- Protective mechanism of glycyrrhizin on acute liver injury induced by carbon tetrachloride in mice. Biol Pharm Bull. 2007 Oct;30(10):1898-904
- Curreli, Francesca; Friedman-Kien, Alvin E.; Flore, Ornella. "Glycyrrhizic acid alters Kaposi sarcoma–associated herpesvirus latency, triggering p53-mediated apoptosis in transformed B lymphocytes" Journal of Clinical Investigation, Vol. 115, Issue 3 (March 1, 2005) 115(3): 642-652 (2005). doi:10.1172/JCI23334.
- Ferrell, Vance; Archbold, Edgar E.; Cherne, Harold M. 'Natural Remedies Encyclopedia' Fourth Edition, page 412.
- Materia Medica, retrieved 24 May 2007
- Farese, S; Kruse, A, Pasch, A, Dick, B, Frey, BM, Uehlinger, DE, Frey, FJ (2009 Oct). "Glycyrrhetinic acid food supplementation lowers serum potassium concentration in chronic hemodialysis patients.". Kidney international 76 (8): 877–84. doi:10.1038/ki.2009.269. PMID 19641483.
- Winston, David; Steven Maimes (2007). Adaptogens: Herbs for Strength, Stamina, and Stress Relief. Healing Arts Press.
- Yokota T, Nishio H, Kubota Y, Mizoguchi M. The inhibitory effect of glabridin from licorice extracts on melanogenesis and inflammation. Pigment Cell Res 11(6):355-61 (1998 Dec).
- Sandeep, T. C.; Joyce L. W. Yau, Alasdair M. J. MacLullich, June Noble, Ian J. Deary, Brian R. Walker, and Jonathan R. Seckl (19 April 2004). "11β-Hydroxysteroid dehydrogenase inhibition improves cognitive function in healthy elderly men and type 2 diabetics". Proceedings of the National Academy of Sciences 101 (17): 6734–6739. doi:10.1073/pnas.0306996101. PMC 404114. PMID 15071189.
- Bensky, Dan; et al. (2004). Chinese Herbal Medicine: Materia Medica, Third Edition. Eastland Press. ISBN 0-939616-42-4.
- Brush, Mendenhall E, Guggenheim A, Chan T, Connelly E, et.al., The effect of Echinacea purpurea, Astragalus membranaceus and Glycyrrhiza glabra on CD69 expression and immune cell activation in humans, Phytother Res. 2006 Jun 28, Pubmed ID: 16807880.
- Das, S.K.; Das V, Gulati AK & Singh VP (1989). "Deglycyrrhizinated liquorice in aphthous ulcers". The Journal of the Association of Physicians of India (Association of Physicians of India) 37 (10): 647. PMID 2632514.
- Krausse, R.; Bielenberg J. Blaschek W. & Ullmann U. (2004). "In vitro anti-Helicobacter pylori activity of Extractum liquiritiae, glycyrrhizin and its metabolites". Journal of Antimicrobial Chemotherapy (Oxford University Press) 54 (1): 243–246. doi:10.1093/jac/dkh287. PMID 15190039.
- Robert Proctor on NPR's Science Friday
- The Nurse's Guide To Herbal Remedies from Salisbury University
- Liquorice and hypertension Editorial in The Netherlands Journal of Medicine, 2005
- A Guide to Medicinal and Aromatic Plants from Purdue University
- Subhuti Dharmananda, Ph.D., Safety Issues Affecting Herbs: Herbs that May Increase Blood Pressure, retrieved 14 May 2010
- Woman 'overdoses' on liquorice, BBC News online, published Friday, 21 May 2004
- Sigurjónsdóttir, H.A., et al. Liquorice-induced rise in blood pressure: a linear dose-response relationship. Journal of Human Hypertension (2001) 15, 549-552.
- BBC Woman 'overdoses' on liquorice 21 May 2004
- Eurekalert press release 2009
|Wikimedia Commons has media related to: Liquorice|
- National Institute of Health - Medline
- PDRhealth.com - Profile of Deglycyrrhizinated Licorice (DGL)
- Chemical & Engineering News article on Licorice
- Non-profit site on the health aspects of licorice/liquorice
- Medical use of irritation on chest