Glycyrrhiza glabra l. Family: Fabaceae
licorice, sweet root
Licorice is a herbaceous perennial. It’s grown in southeastern Europe and western Asia. It’s been used since ancient times as a flavoring agent. It’s also been used as an expectorant.
The medicinal parts of the plant are the unpeeled dried roots and runners, and the rhizome (underground stem). Licorice contains the compound glycyrrhizin. This is 50 times sweeter than sugar. Taking in too much glycyrrhizin glycoside from eating too much licorice can cause fluid retention and high blood pressure (hypertension).
Medically valid uses
The primary use of licorice is as a flavoring agent. It’s used in products such as toothpaste, throat lozenges, and tobacco. (Most "licorice" candy is flavored with anise oil and not real licorice.)
A few clinical trials outside the U.S. show that an injectable form of licorice extract may help treat the hepatitis C virus. But more research is needed.
Please note that this section reports on claims that have not yet been substantiated through studies.
Licorice has been linked with a wide range of claims. It may help the following issues:
Ease a cough and bronchitis
Reduce inflammation, especially in the stomach
Lower high cholesterol and triglyceride levels
Prevent plaque and tooth decay
Treat microbial or viral infections, including viral liver disease
Protect your liver
Treat snake bites. It may be used as an anti-venom.
Suppress your immune system
Treat tetanus and globefish toxins
Act as a cocaine hydrochloride and chloral hydrate
Aid in treating skin issues (when applied topically)
Follow the dosing instructions on the label.
Side effects, toxicity, and interactions
Licorice can cause serious side effects if you take too much of it or use it for too long. It has an aldosterone-like effect. This causes sodium retention and potassium loss.
Excessive use of licorice can lead to high blood pressure. This can be severe. It can cause the following symptoms:
Swelling due to water retention (edema)
Lack of energy (lethargy)
Heart failure or cardiac arrest
You can even become poisoned from consuming too much real licorice-containing candy or licorice-containing tobacco.
You shouldn’t take licorice if you have certain health issues. These include the following:
Low potassium levels (hypokalemia)
Cholestatic liver disease
Heart rhythm issues and other heart diseases
High blood pressure
Severe kidney problems
A tumor in your adrenal glands called a pheochromocytoma
You also shouldn’t take it if you consume a lot of alcohol. Women who are pregnant or breastfeeding also shouldn’t use this herb.
Don’t take licorice while fasting. Doing so can lead to a serious electrolyte imbalance.
Licorice can also interact with some medicines. Thiazide diuretics may increase potassium loss when used with licorice. Licorice may also increase the effects of digitalis. This is because digitalis sensitivity is increased by low potassium levels.
Licorice may interfere with the effects of aldactone. This is a medicine used to treat high blood pressure. Talk to your healthcare provider before you take licorice.
You also shouldn’t take licorice if you take warfarin. It may increase your metabolism and decrease levels of warfarin.
March 21, 2017
Apparent mineralocorticoid excess syndromes (including chronic licorice ingestion). UpToDate.
Poulson, Brittany, RD, CDE,Wilkins, Joanna, R.D., C.D.