Licorice is a plant that grows in southern Europe, Asia, and the Mediterranean. The dried licorice roots and underground stems are used in herbal remedies. In China, licorice root is used for stomach ulcers, dry cough and to detoxify other herbs and drugs.

Benefits
Licorice has compounds that can enhance the immune system, provide antioxidant support, support healthy levels of cholesterol, and thin the blood. It may even support brain power (see below). Licorice appears to play some role in peptic ulcers.

Adv Pharm Bull. 2013. Protective Effect against Hydroxyl-induced DNA Damage and Antioxidant Activity of Radix Glycyrrhizae (Liquorice Root).

Anti-inflammatory
Glycyrrhizin, an aqueous extract of licorice root, has anti-inflammatory activity and has been used for the treatment of chronic viral hepatitis. Glycyrrhizin inhibited the cytolytic activity of complement via the activation of both the classical and alternative pathways, while it had no effect on immune adherence, suggesting that it blocks C5 or a later stage of the complement cascade. Further analysis revealed that glycyrrhizin inhibits the lytic pathway in which the membrane attack complex (MAC) is formed. This mechanism suggests that glycyrrhizin may prevent tissue injury caused by MAC not only in chronic hepatitis but in many autoimmune and inflammatory diseases.

Cough remedy
Pharmacokinetic and pharmacodynamic profiles of the antitussive principles of Glycyrrhizae radix, main component of the Kampo preparation Bakumondo-to (Mai-men-dong-tang).
Eur J Pharmacology. 2005.
We examined the pharmacokinetic and pharmacodynamic properties of liquiritin apioside, a main antitussive component of Glycyrrhizae radix, with regard to its antitussive effect in guinea pigs. The present results suggest that licorice may produce a persistent antitussive effect, and that liquiritin apioside plays an important role in the earlier phase, while liquiritigenin, which is a metabolite of liquiritin apioside and liquiritin, plays an important role in the late phase.

GI health, stomach, intestines
I read somewhere that deglycyrrhizinated licorice root could be helpful for someone who is taking NSAID medications to help reduce stomach ulcers, is this true?
    DGL may be helpful but I would like to see more studies.

Hormone level influence
Mol Cell Endocrinology. 2011. Liquorice and glycyrrhetinic acid increase DHEA and deoxycorticosterone levels in vivo and in vitro by inhibiting adrenal SULT2A1 activity. The glycyrrhetinic acid constituent of liquorice increases circulating and thereby, salivary levels of unconjugated deoxycorticosterone and dehydroepiandrosterone by inhibiting their conjugation at source within the adrenal cortex. This effect may contribute to the mineralocorticoid actions of glycyrrhetinic acid and gives substance to claims that liquorice also has androgenic properties.

Oral Health
Compounds from the Chinese herb, Glycyrrhiza uralensis, which is commonly referred to as Chinese licorice, appear to be effective in fighting bacteria that cause tooth decay since it has antibacterial compounds. Chewing licorice has been a practice in different cultures. Two compounds in it inhibit the growth of Streptococcus mutans, the primary bacteria responsible for causing cavities. In fact, licorice root's antimicrobial activity was seen in a number of experiments, including those involving human saliva and dental plaques. Source: Journal of Natural Products, 2006.

Two predominant compounds, licoricidin and licorisoflavan A, are effective in inhibiting the growth of cavity-causing bacteria.

What's in Licorice Root?
There are many compounds: Licorice flavonoids mainly include flavones, flavonals, isoflavones, chalcones, bihydroflavones and bihydrochalcones. Pharmacological investigation indicates that they have antioxidant, antibacterial, anti-tumor and HIV inhibiting activities. Two natural isoflavone compounds derived from licorice root, glabridin and glabrene, demonstrate estrogen-like activities. Various extracts are available including 12%~26% glycyrrhizic acid.

Licorice side effects and caution, safety, danger, headache
High doses of licorice when used daily over a prolonged period can cause a fluid imbalance in the body, involving salt, potassium, and water metabolism. Licorice-associated hypertension is thought to be due to increased renal sodium retention. The active compound glycyrrhetinic acid inhibits renal 11beta-hydroxysteroid dehydrogenase type 2 and by that mechanism increases access of cortisol to the mineralocorticoid receptor that causes renal sodium retention and potassium loss. Basically this means that too much licorice used for prolonged periods leads to loss of potassium in the urine and the retention of sodium. Sometimes this is described as pseudoaldosteronism.
    Another reported side effect of chronic high dose licorice use is rhabdomyolisis which is damage to muscle tissue.

Headache is common: I have personally noticed headache after several days of drinking licorice tea, usually two bags at a time. This has happened on multiple occasions and the headache subsided a day after I stopped drinking.

Duodecim. 2015. Licorice as the cause of elevated blood pressure and headache. Physicians are familiar with the effect on potassium metabolism of glycyrrhizine acid contained in licorice and salmiac. Even so, glycyrrhizine acid as the cause of even severe symptoms may escape attention, especially in an emergency situation. We describe a patient, who sought medical advice from an endocrinologist for recurrent, severe and symptomatic hypertension. After the patient had stopped eating salmiac and licorice, the headache that had persisted for years disappeared, fluctuations in weight stabilized and occasional edemas of the lower limbs vanished. Since the cessation of using licorice products normalized the blood pressure, it is likely that the patient had licorice-induced hypertension.

Do you know if licorice herb or products, or one of its varieties, can trigger heart palpitations?
    Heart rhythm disturbances are possible in high dosages used regularly.

I wish to purchase the deglycyrrhizinated licorice root product. I currently have high blood pressure. I just wanted to confirm that this will not raise blood pressure.
   I have no good reason to believe this would increase blood pressure but it is impossible for us to make a 100 percent guarantee in any one individual.

I took a licorice herbal pill for over a week. They were dgl but still gave me symptoms of high blood pressure, headache, dizziness, and tight muscles. My blood pressure would go up randomly and fall back down after a while. My BP is normally 110/73. Highest rise I got was 155/99. I could feel my BP rise and a lot of pressure when it did. After two weeks my symptoms were gone and I felt good. Just more anxious than normal. I suffer from general anxiety. After three weeks while I am laying in bed I feel the same symptoms and check my BP it's 120/93 and for the week I've felt the same symptoms though they have been less severe but still I can't do much. I take 50 zoloft and a vitamin d supplement daily. Otherwise I am very healthy. Any thoughts as to why they came back? I haven't had one of those licorice pills for weeks.
   A. Generally the side effects of licorice go away within days of stopping it. Perhaps the Zoloft has an effect but it is difficult for me to say without doing a full history and exam.

Pregnancy
Q. I have a question. I'm 2 months pregnant, and have bad morning sickness. I went on a website where they recommended herbal pills to help subside morning sickness. The herbal pills have licorice in them, will it effect my unborn baby?
   A. Ginger has been tested for morning sickness. Licorice may not be a good idea to use during pregnancy due to possible increase in the risk for preterm birth. Occasional use would be fine, but regular, heavy use is discouraged.

Preterm birth and licorice consumption during pregnancy.
Am J Epidemiology. 2002.
Heavy licorice consumption was associated with an increased risk of preterm delivery.

Licorice Root Human research study
Licking latency with licorice.
J Clin Invest. 2005.
Numerous viruses cause latent infections in humans, and reactivation often results in pain and suffering. While vaccines for several of these viruses are available or currently being studied in clinical trials, and antiviral therapies have been successful in preventing or treating active infection, therapy to eradicate latent infection has lagged behind. A new study reported in this issue of the JCI shows that treatment of cells latently infected with Kaposi sarcoma-associated herpes virus (KSHV) with glycyrrhizic acid, a component of licorice root, reduces synthesis of a viral latency protein and induces apoptosis of infected cells. This finding suggests a novel way to interrupt latency.

Memory-strengthening activity of Glycyrrhiza glabra in exteroceptive and interoceptive behavioral models.
J Med Food. 2004.
In the traditional system of medicine, the roots and rhizomes of Glycyrrhiza glabra - licorice plant - have been employed clinically for centuries for their anti-inflammatory, anti-ulcer, expectorant, antimicrobial, and anxiolytic activities. The present study was undertaken to investigate the effects of G. glabra, popularly known as licorice (Mulathi), on learning and memory. The elevated plus-maze and passive avoidance paradigm were employed to evaluate learning and memory parameters. Three doses (75, 150, and 300 mg/kg p.o.) of aqueous extract of Glycyrrhiza glabra were administered for 7 successive days in separate groups of mice. The dose of 150 mg/kg of the aqueous extract of licorice significantly improved learning and memory of mice. Furthermore, this dose reversed the amnesia induced by diazepam (1 mg/kg i.p.), scopolamine (0.4 mg/kg i.p.), and ethanol. Anti-inflammatory and antioxidant properties of licorice may be contributing favorably to the memory enhancement effect. Since scopolamine-induced amnesia was reversed by licorice, it is possible that the beneficial effect on learning and memory may be because of facilitation of cholinergic transmission in brain. However, further studies are necessitated to identify the exact mechanism of action. In the present investigation, licorice root has shown promise as a memory enhancer in both exteroceptive and interoceptive behavioral models of memory.

Licorice reduces serum testosterone in healthy women.
Steroids. 2004.
The most common side effect is hypokalemic hypertension, which is secondary to a block of 11beta-hydroxysteroid dehydrogenase type 2 at the level of the kidney, leading to an enhanced mineralocorticoid effect of cortisol. We have investigated the effect of licorice on androgen metabolism in nine healthy women 22-26 years old, in the luteal phase of the cycle. They were given 3.5 g of a commercial preparation of licorice (containing 7.6% W.W. of glycyrrhizic acid) daily for two cycles. Licorice can reduce serum testosterone probably due to the block of 17-hydroxysteroid dehydrogenase and 17-20 lyase. Licorice could be considered an adjuvant therapy of hirsutism and polycystic ovary syndrome.

Licorice Flavonoids Suppress Abdominal Fat Accumulation and Increase in Blood Glucose Level in Obese Diabetic KK-A(y) Mice.
Biol Pharm Bull. 2004.
Licorice, the root of the Glycyrrhiza species, is one of the most frequently employed botanicals in traditional medicines. In this study, we investigated the effects of hydrophobic flavonoids from licorice on abdominal fat accumulation and blood glucose level in obese diabetic mice. In order to enrich a fraction of hydrophobic flavonoids, licorice flavonoid oil was prepared by further extracting licorice ethanolic extract with medium-chain triglycerides (MCT), and adjusting the concentration of glabridin, the major flavonoid of licorice, to 1.2% in oil. Mice aged 6 weeks were assigned to 5 groups, and fed a high-fat diet containing 0 (control), 0.5%, 1%, or 2% licorice flavonoid oil, or 0.5% conjugated linoleic acid (CLA) for 4 weeks. Compared with the control, body weight gain and weights of abdominal adipose tissues were suppressed by feeding the diet containing 2% licorice flavonoid oil , and blood glucose levels after 2 and 4 weeks were suppressed by all of the diets containing licorice flavonoid oil. Although CLA feeding suppressed body weight gain, it increased blood glucose level after 2 weeks compared with the control level. Furthermore, licorice flavonoid oil and licorice ethanolic extract stimulated human adipocyte differentiation in vitro. These results indicate that licorice hydrophobic flavonoids have abdominal fat-lowering and hypoglycemic effects, possibly mediated via activation of peroxisome proliferator-activated receptor-gamma (PPAR-gamma).

Inhibition of serotonin re-uptake by licorice constituents.
J Mol Neurosci. 2003.
The aim of this study was to test the effect of compounds of the licorice isoflavan and isoflavene groups, subclasses of the flavonoids family, on serotonin re-uptake and to compare the results with the effect of other known phytoestrogens like genistein and daidzein to relate the activity of these compounds to their structure. The results demonstrated that the isoflavans glabridin and 4'-O-methylglabridin (4'-OMeG) and the isoflavene glabrene inhibited serotonin re-uptake, whereas resorcinol, the isoflavan 2'-O-methylglabridin (2'-OMeG), and the isoflavones genistein and daidzein were inactive. In conclusion, this study showed that several licorice isoflavans are unique phytoestrogens, which like estradiol, affects the serotonergic system and inhibits serotonin re-uptake and, thus, potentially may be beneficial for mild to moderate depression in pre- and postmenopausal women.

Effect of licorice on the reduction of body fat mass in healthy subjects.
J Endocrinol Invest. 2003.
The history of licorice, as a medicinal plant, is very old and has been used in many societies throughout the millennia. The active principle, glycyrrhetinic acid, is responsible for sodium retention and hypertension, which is the most common side-effect. We show an effect of licorice in reducing body fat mass. We studied 15 normal-weight subjects (7 males, age 22-26 yr, and 8 females, age 21-26 yr), who consumed for 2 months 3.5 g a day of a commercial preparation of licorice. Body fat mass (BFM, expressed as percentage of total body weight, by skinfold thickness and by bioelectrical impedance analysis, BIA) and extracellular water (ECW, percentage of total body water, by BIA) were measured. Body mass index (BMI) did not change. ECW increased. BFM was reduced by licorice; plasma renin activity and aldosterone were suppressed. Licorice was able to reduce body fat mass and to suppress aldosterone, without any change in BMI. Since the subjects were consuming the same amount of calories during the study, we suggest that licorice can reduce fat by inhibiting 11beta-hydroxysteroid dehydrogenase Type 1 at the level of fat cells.

Anti-atherosclerotic effects of licorice extract supplementation on hypercholesterolemic patients: increased resistance of LDL to atherogenic modifications, reduced plasma lipid levels, and decreased systolic blood pressure.
Nutrition 2002
We previously demonstrated the beneficial effects of dietary flavonoids derived from the ethanolic extract of licorice root against atherosclerotic lesion development in association with inhibition of low-density lipoprotein (LDL) oxidation in atherosclerotic mice. Administration of licorice extract to normolipidemic subjects also inhibited LDL oxidation. In the present study, we extended our investigation to analyze the anti-atherogenic effects of licorice-root extract consumption in moderately hypercholesterolemic patients. Supplementation of licorice root extract (0.1 g/d) to patients for 1 mo was followed by an additional 1 mo of placebo consumption. Licorice consumption reduced patients' plasma susceptibility to oxidation (by 19%); increased resistance of plasma LDL against three major atherogenic modifications: oxidation (by 55%), aggregation (by 28%), and retention, estimated as chondroitin sulfate binding ability (by 25%); reduced plasma cholesterol levels (by 5%), which was due to a 9% reduction in plasma LDL cholesterol levels; and reduced (by 14%) plasma triacylglycerol levels. After the 1 mo of placebo consumption, these parameters reversed toward baseline levels. Licorice extract supplementation also reduced systolic blood pressure by 10%, which was sustained during the placebo consumption. Dietary consumption of licorice-root extract by hypercholesterolemic patients may act as a moderate hypocholesterolemic nutrient and a potent antioxidant agent and, hence against cardiovascular disease.

Effects of prolonged ingestion of graded doses of licorice by healthy volunteers.
Patologia Speciale Medica I, University of Bologna. Life Sci. 1994.
Licorice can induce a hypermineralocorticoid syndrome. Current literature usually refers to the effects of sweets containing glycyrrhizin, but little is known about the consequences of a prolonged intake of "pure licorice". We administered graded daily doses of dried, aqueous extract of licorice root, containing 108, 217, 380 and 814 mg of glycyrrhizin, to 4 groups of 6 healthy volunteers of both sexes for 4 weeks. No significant effects occurred in groups 1 and 2. After 2 weeks, side effects leading to withdrawal from the protocol occurred in a female in group 3 (headache), a male with a family history of hypertension in group 4 (arterial hypertension), and a female also taking oral contraceptives in group 4 (hypertension, hypokalaemia and peripheral edema). In group 4, transient reduction in kalaemia and increase in body weight were found after 1 and 2 weeks, respectively. A depression of plasma renin activity occurred in groups 3 and 4. In healthy subjects, only the highest doses of licorice led to untoward effects. These were favored by subclinical disease or oral contraceptives, and were less common and pronounced than what has been reported after the intake of glycyrrhizin taken as such or as a flavoring agent in confectionery products.

The ingestion of licorice, and/or its active metabolites, can sometimes produce an acquired form of apparent mineralocorticoid excess (AME) syndrome, expressed as sodium retention, potassium loss and suppression of the renin-angiotensin-aldosterone system, in addition to clinical consequences such as raised blood pressure and oedema.

Animal Studies
Memory enhancing activity of Glycyrrhiza glabra in mice.
J Ethnopharmacol. 2004.
In the traditional system of medicine, the roots and rhizomes of Glycyrrhiza glabragh have been employed clinically for centuries for their anti-inflammatory, antiulcer, expectorant, antimicrobial and anxiolytic activities. The present study was undertaken to investigate the effects of Glycyrrhiza glabra (popularly known as liquorice) on learning and memory in mice. Elevated plus-maze and passive avoidance paradigm were employed to test learning and memory. Three doses (75, 150 and 300 mg/kg p.o.) of aqueous extract of Glycyrrhiza glabra were administered for 7 successive days in separate groups of animals. The dose of 150 mg/kg of the aqueous extract of liquorice significantly improved learning and memory of mice. Furthermore, this dose significantly reversed the amnesia induced by diazepam (1 mg/kg i.p.) and scopolamine (0.4 mg/kg i.p.). Anti-inflammatory and antioxidant properties of liquorice may be contributing favorably to the memory enhancement effect. Since scopolamine-induced amnesia was reversed by liquorice, it is possible that the beneficial effect on learning and memory was due to facilitation of cholinergic-transmission in mouse brain. However, further studies are necessitated to identify the exact mechanism of action. In the present investigation, Glycyrrhiza glabra has shown promise as a memory enhancing agent in all the laboratory models employed.

Antithrombotic effect of Glycyrrhizin, a plant-derived thrombin inhibitor.
Thromb Res. 2003.
Glycyrrhizin, an anti-inflammatory compound isolated from licorice (Glycyrrhiza glabra), has been previously identified as a thrombin inhibitor. Here we report the in vivo effects of GL upon two experimental models of induced thrombosis in rats. Intravenous administration of GL caused a dose-dependent reduction in thrombus size on a venous thrombosis model that combines stasis and hypercoagulability. It was observed that GL doses of 180 mg/kg body weight produced 93% decrease on thrombus weight. GL doses above 90 mg/kg caused significant hemorrhagic effect. In contrast with heparin, GL did not potentiate the inhibitory activity of antithrombin III or heparin cofactor II towards thrombin. Altogether, data indicate that glycyrrhizin is an effective thrombin inhibitor in vivo, which may account for its other known pharmacological properties.

Glycyrrhizin, an active component of licorice root, reduces morbidity and mortality of mice infected with lethal doses of influenza virus.

Laboratory Studies
A compound derived from licorice root may help slow the effects of aging on the brain and keep mental skills sharp. Researchers found the compound, known as carbenoxolone, appears to inhibit an enzyme in the brain that is involved in making stress-related hormones, which have been associated with age-related mental decline. The study, published in the online early edition of the Proceedings of the National Academy of Sciences, showed daily supplementation with the compound improved verbal fluency in healthy elderly men and improved verbal memory in older adults with diabetes.

A compound isolated from the root of the licorice plant could be more effective than current treatments for SARS, the virus that has killed 780 people worldwide. Glycyrrhizin, or licorice root, is already given to patients suffering from HIV and hepatitis C. Researchers at Frankfurt University Medical School now believe licorice could help to combat SARS. --The Lancet medical journal.

Sous is a drink served in Jordan and Middle Eastern countries with licorice root. You can make your own licorice root drink by buying the cut up licorice root sold in bulk in health food stores and then soak it in water.
Licorice also comes in black licorice and licorice candy

Emails
Q. I purchased Natures Energy and it has licorice extract 12.5mg. I wanted to take this vitamin but I am not sure if this herb will hurt me in anyway?
   A. Occasional use of licorice is healthy, daily use may cause problems in electrolyte balance as discussed above.

Q. How many weeks can i take licorice and how many weeks should i take a break before i can take licorice again?
   A. As a general rule, taking licorice 3 days a week is fine, or, if you take it daily, taking at least a week off each month is a good idea but these are general guidelines and much depends of the amount of licorice that is being consumed and whether you are taking other medicines, water pills, and your general health and kidney function.

Q. I do have high blood pressure. I was looking to buy a formula from a company Herbasway.com, called Liver Enhancer which is a tincture that contains some Chinese herbs and Chinese Licorice. (10mgs lic per dropper) I would be taking 2 or 3 droppers a day.  I was told by that company, that the Chinese LIcorice is different from the American Licorice in that it cannot raise blood pressure. In your opinion, is this really true?
   A. I have not seen any research regarding a comparison between Chinese licorice or licorice from other sources.

I've been having some stomach problems. I am not usually a person with a fragile stomach, but my digestion has been poor for the last few months, and heartburn for the first time in my life. I don't drink milk, just yogurt, very little cheese, some cottage cheese, so I doubt that it's lactose intolerance. I thought maybe wheat but I very rarely eat sandwiches made with bread, usually I take leftover dinner to work as lunch, so I don't eat out much (and never fast food!!). We eat very little red meat, usually fish or chicken. Besides bad digestion, I have been experiencing lethargy to a degree that affects my life--I just don't have energy to get any chores done, although I have been sleeping better than usual. And gassy feeling in my intestines, part of the indigestion symptoms. Also constipated if I don't take my usual nightly psyllium husks drink. Thinking about what is regular in my diet I thought about my tea. I really like iced tea. I make it myself at home and take it to work. (Don't drink sodas.) A few months ago, don't remember exactly, I discovered licorice root at my tea store. I had been brewing my tea with peppermint, green tea, maybe a regular pekoe tea bag. I like licorice because it's sweet and I never put sugar in my tea, so this was a bonus sweetener. I had read about all the things licorice is good for. But now I'm wondering if I've been drinking too much. I have no idea how many grams/day I've been drinking. I take several slices of the root and boil it for 10 minutes, strain it and mix it with some other brew, usually regular pekoe tea bags, in a gallon container. I drink maybe 6 or more cups of this a day.  I've been drinking this licorice-based tea brew for months now, maybe 5 months? Is that too much licorice?
    I cannot advise anyone what to drink or how much, but excess licorice use does have adverse effects. I prefer alternating between different teas rather than consuming the same one all the time.

As recommended by my naturopath, I have been taking half a teaspoon of licorice extract 4 times a day for one week. A week ago I developed severe headaches, swollen ankles, nausea, lethargy and racing heart episodes. On a hunch, I discontinued taking the licorice. After reading your website information on this supplement as well as other websites, I now recognize that I have been suffering from the side effects of licorice consumption. Before I researched the side effects, I saw my physician yesterday who was not knowledgeable about licorice and its potential serious side effects. My blood pressure and pulse were normal. My question for you is, how do I remedy the damage I have done in taking this supplement in this high dosage? What can I do to feel better? (I stopped taking the licorice extract as soon as I got the headache a week ago on a hunch that it could be related.) Have I caused any permanent damage to myself? I would appreciate your advice and recommendations. I'd appreciate your recommendations of further research for me to read.
    It is not possible for me to know exactly what damage, if any, has occurred, but, in most cases stopping the short term licorice consumption can completely reverse the symptoms and signs.

Thank you so much for providing such a wonderfully informative web site. I read through your info on DGL (Deglycyrrhizinated licorice) but did not see my question addressed. I understand that DGL has the element removed that can cause high blood pressure but I am wondering if DGL would have any significant estrogenic effects? I know that licorice candy is recommended for menopause symptoms of low estrogen but I do not know if this estrogenic like effect is still present in DGL? Any info you could provide would be most appreciated.
   A. As of 2016 I do not know the answer.

buy Licorice Root Extract- Deglycyrrhizinated - 380 mg
200 Chewable Tablets
Planetary Formulas

Research has shown that deglycyrrhizinated licorice root supports and promotes healthy stomach lining and intestinal flora. Glycyrrhiznic and glycyrrhetinic acids, substances in licorice root associated with high blood pressure, have been removed. Planetary Formulas professional strength DGL lirorice extract reflects dosages and preparations used in clinical studies. Also consider Acai supplement, mangosteen, noni, and Pomegranate.

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Supplement Facts
Licorice - Deglycyrrhizinated 380 mg Licorice Root Extract (10:1)
Suggested Use: Chew one licorice tablet before breakfast and / or lunch, or as recommended by your health care professional.