Licorice Root (Glycyrrhiza glabra): Uses, Evidence and Safety

Safety first: real licorice can raise blood pressure and lower potassium. Licorice contains glycyrrhizin, which can cause serious effects such as irregular heartbeat and cardiac arrest, especially in large amounts or over a long time. [1] Even small amounts have been linked to severe effects in people who eat a lot of salt, people with high blood pressure and people with heart or kidney conditions. [1] If you have chest pain, a very irregular heartbeat, fainting or severe muscle weakness, call 911 (US). Ask a pharmacist before using licorice if you take diuretics ("water pills"), heart-rhythm medicines, corticosteroids or blood pressure medicines. See how herb and medicine interactions work.

Overview

Licorice (also spelled liquorice) is a perennial herb whose root is used as a flavoring in candy, other foods and tobacco, and as a traditional medicine. [1] Many "licorice" products sold in the United States do not contain actual licorice; anise oil, which smells and tastes similar, is often used instead. [1] This page is about the root of the plant, not candy flavored with anise. Tea made from the root has its own page: licorice root tea. Licorice hidden in blends is covered in licorice in tea blends and blood pressure.

Names, plant part and family

The accepted botanical name is Glycyrrhiza glabra L., in the pea family (Fabaceae). [2] The part used is the root. NCCIH also lists two other species under the same common name, Glycyrrhiza uralensis and Glycyrrhiza inflata. [1] The EU herbal monograph covers all three. [3] "Gan cao" is the Chinese name for licorice root. [1] Results for one species or one extract do not automatically carry over to another. For the traditions, see licorice in Chinese medicine and licorice (mulethi) in Ayurveda. Adaptogen-style claims for licorice are not assessed here; see Adaptogens.

Traditional use (not proof)

NCCIH says licorice root has a long history of use going back to ancient Assyrian, Egyptian, Greek, Arab, Chinese, Tibetan and Indian cultures. [1] It was used in traditional medicine for coughing, asthma and wound healing, and for diseases of the lungs, liver and arteries. [1] In the European Union, a committee of the European Medicines Agency (the HMPC) accepts a traditional herbal use as an expectorant in cough associated with a cold, and for digestive symptoms, based only on long-standing use. [4] Long-standing use is not the same as trial evidence.

What research shows

NCCIH says some studies in people have been done, but there is not enough high-quality evidence to clearly support licorice for any health condition. [1]

The blood pressure and potassium problem

A systematic review of 18 studies (337 people) found a rise in average systolic blood pressure of 5.45 mm Hg and a drop in plasma potassium after regular intake of a glycyrrhizic-acid product. [5] A later randomized crossover trial in 28 healthy volunteers tested a daily licorice intake containing 100 mg of glycyrrhizic acid for two weeks. Home systolic blood pressure rose and the hormones renin and aldosterone were suppressed. [6] The authors noted that the World Health Organization had suggested 100 mg a day would be unlikely to cause adverse effects, and concluded the trial found licorice more potent than previously known. [6] A review of 104 case reports found that continued intake of large amounts causes pseudo-hyperaldosteronism (a state that mimics excess of a salt-holding hormone) leading to high blood pressure and low potassium, and that some cases led to arrhythmias, muscle paralysis and coma. [7] Reports of lethal arrhythmia and cardiac arrest after heavy licorice use are listed by Memorial Sloan Kettering. [8] These figures describe study conditions, not an amount that is right for you.

Forms and why the form matters

• Whole root, tea, extract or candy with real licorice: contains glycyrrhizin unless it has been removed.
• Deglycyrrhizinated licorice (DGL): glycyrrhizin has been removed. [9] NCCIH says oral DGL products might be safe for up to 4 months. [1] This is a statement about safety only; we did not assess whether DGL works for any use.
• Mouth rinse, gargle or topical gel: the studied forms for ulcers and skin. Topical licorice root may be safe short term but may irritate the skin. [1]
• Blends: research on a mix says little about licorice alone. [1]

Safety

• Medicines. The EU monograph says licorice may counteract the action of prescribed blood pressure medicines, and that using it with diuretics, cardiac glycosides, corticosteroids, stimulant laxatives or other medicines that can upset electrolytes is not recommended. [4] It also says caution is advised with medicines processed by the liver enzyme CYP3A4. [4] NCCIH reports interactions with corticosteroids. [1] Memorial Sloan Kettering lists further, less certain items: warfarin (clinical relevance not known), cyclosporine (a transplant medicine) and monoamine oxidase inhibitors. [8] Ask a pharmacist; do not change any prescribed medicine yourself.
• Heart, blood pressure, kidney, liver, low potassium. The EU monograph says licorice medication is not recommended in people with high blood pressure, kidney disease, liver or cardiovascular disorders or low potassium, because they are more sensitive to its effects. [4] The US liver database LiverTox says licorice has not been reported to cause liver enzyme rises or clinically apparent liver injury. [10] The kidney and heart cautions still apply. See herbs and kidney disease and herbs with diabetes, blood pressure and heart medicines.
• Pregnancy. NCCIH says oral licorice extract in large amounts (about 250 grams of licorice per week) is unsafe in pregnancy and can raise the risk of delivery before 38 weeks. [1] The EU monograph does not recommend use in pregnancy. [4] See pregnancy and breastfeeding.
• Breastfeeding. Glycyrrhizin is detectable in breastmilk of some women who take licorice. [9] The EU monograph does not recommend use while breastfeeding, and LactMed says long-term excessive use should probably be avoided during nursing. [4][9]
• Children. The EU monograph does not recommend use under 18 because of lack of data. [4] See children and teens.
• Duration. For the digestive use the EU monograph says not to use for more than 4 weeks. [4] It reports overdose cases with prolonged use or high intake. [4]
• Surgery. Tell the surgical team about any licorice product, especially if you also take blood pressure or heart medicines. See supplements before surgery.
• Allergy. The EU monograph lists hypersensitivity to licorice as a contraindication. [4]

Quality

Supplements are not approved by FDA before sale, and makers are responsible for safety and labeling. [1] Check the species and whether glycyrrhizin has been removed. See quality testing and certifications.

Official statements

• European Medicines Agency, HMPC (EU), 2026: revised EU herbal monograph adopted 4 March 2026 for Glycyrrhiza glabra, G. inflata and G. uralensis root, as a traditional herbal medicinal product for digestive symptoms and as an expectorant in cough with a cold, with cautions above. [4]
• NCCIH (US National Institutes of Health): not enough high-quality evidence for any health condition; glycyrrhizin cautions. [1]