Glycyrrhiza glabra l. Family: Fabaceae

licorice, sweet root

Licorice is a perennial herb. It’s mostly grown in Greece, Turkey, 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 underground stem (rhizome). 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 you to retain fluid and raise your blood pressure (hypertension).

Licorice is mainly used 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 licorice extract given as a shot may help treat the hepatitis C virus. But more research is needed.

Note that this section reports on claims that have not yet been proved through studies.

Licorice has been linked with a wide range of claims. It may help the following issues:

• Ease a cough and bronchitis

• Treat allergies

• Reduce inflammation, especially in the stomach

• Lower high cholesterol and triglyceride levels

• Prevent plaque, gum disease, and tooth decay

• Treat microbial or viral infections, including viral liver disease

• Protect your liver

• Treat snakebites. It may be used as an antivenin.

• Suppress your immune system

• Treat tetanus and globefish toxins

• Act as a possible antidote for the toxic effects of cocaine abuse

• Aid in treating skin issues when put on the skin

Licorice comes in capsules and tablets, and as a liquid extract. Follow the dosing instructions on the label.

Licorice can cause serious side effects if you take too much of it or use it for too long. It has an effect similar to aldosterone. Aldosterone is a hormone that causes your body to retain salt (sodium) and lose potassium.

Taking too much licorice can cause high blood pressure. This can be severe. It can cause the following symptoms:

• Swelling because your body is retaining water (edema)

• Headache

• Lack of energy (lethargy)

• Heart failure or cardiac arrest

You can even become poisoned from eating too much candy that contains real licorice or using licorice-containing tobacco.

You shouldn’t take licorice if you have certain health issues. These include:

• Low potassium levels (hypokalemia)

• Chronic hepatitis

• Cholestatic liver disease

• Liver cirrhosis

• Heart rhythm issues and other heart diseases

• High blood pressure

• Severe kidney problems

• A tumor in your adrenal glands (pheochromocytoma)

• Aldosteronism

• Untreated hypothyroidism

You also shouldn’t take it if you drink 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 water pills (diuretics) may increase amount of potassium you lose 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 with 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.