Licorice

Licorice is a plant. You are probably most familiar with it as a flavoring in foods, beverages, and tobacco. The root is used to make medicine.

Licorice is used for various digestive system complaints including stomach ulcers, heartburn, colic, and ongoing inflammation of the lining of the stomach (chronic gastritis).

Some people use licorice for sore throat, bronchitis, cough, and infections caused by bacteria or viruses.

Licorice is also used for osteoarthritis, systemic lupus erythematosus (SLE), liver disorders, malaria, tuberculosis, food poisoning, and chronic fatigue syndrome (CFS).

Licorice is sometimes used along with the herbs Panax ginseng and Bupleurum falcatum to improve the function of the adrenal glands, especially in people who have taken steroid drugs long-term. Steroids tend to suppress the activity of the adrenal glands. The adrenal glands produce important hormones that regulate the body’s response to stress.

Licorice is also used in an herbal form called Shakuyaku-kanzo-to to increase fertility in women with a hormonal disorder called polycystic ovary syndrome. In combination with other herbs, licorice is also used to treat prostate cancer and the skin disorder known as eczema.

Some people use licorice as a shampoo to reduce oiliness in their hair.

Many “licorice” products manufactured in the U.S. actually don't contain any licorice. Instead, they contain anise oil, which has the characteristic smell and taste of “black licorice.”

Licorice interacts with many prescription medicines. Talk to your healthcare provider if you plan to start using licorice.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.

The effectiveness ratings for LICORICE are as follows:

• Muscle cramps. Preliminary clinical research suggests taking a specific combination of licorice and peony (Shakuyaku-kanzo-to) might reduce muscle cramps in people with liver disease (hepatic cirrhosis) or in people undergoing treatment for kidney failure (hemodialysis).
• Hepatitis. There is some evidence that some of the chemicals in licorice might be effective in treating hepatitis B and hepatitis C when given intravenously (by IV). But the studies involved too few patients to draw firm conclusions.
• Stomach ulcers. There is some evidence that specially prepared licorice will speed the healing of stomach ulcers.
• Weight loss. There is conflicting information about the use of licorice for weight loss. Licorice seems to reduce body fat. However, it causes water retention that can offset any change in body weight.
• Atopic dermatitis (eczema). There is conflicting evidence about the effectiveness of licorice for treating eczema.
• Arthritis.
• Lupus.
• Infections.
• Infertility.
• Cough.
• Chronic fatigue syndrome (CFS).
• Prostate cancer.
• Other conditions.

More evidence is needed to rate the effectiveness of licorice for these uses.

The chemicals contained in licorice are thought to decrease swelling, thin mucus secretions, decrease cough, and increase the chemicals in our body that heal ulcers.

Licorice is LIKELY SAFE for most people when consumed in amounts found in foods. It is POSSIBLY SAFE when consumed in larger amounts use as medicine, short-term. However, it is POSSIBLY UNSAFE when used in large amounts for more than four weeks. Consuming 30 grams or more of licorice daily for several weeks can cause severe side effects including high blood pressure, low potassium in the blood, weakness, paralysis, and occasionally brain damage in otherwise healthy people. In people who eat a lot of salt or have heart disease, kidney disease, or high blood pressure, as little as 5 grams per day can cause these problems.

Other side effects of licorice use include tiredness, absence of a menstrual period in women, headache, water and sodium retention, and decreased sexual interest and function in men.

People who chew tobacco flavored with licorice might develop high blood pressure and other serious side effects.

Special precautions & warnings:

Pregnancy and breast-feeding: It is UNSAFE to take licorice by mouth if you are pregnant. It might cause a miscarriage or early delivery. Not enough is known about the safety of licorice during breast-feeding. Don’t use licorice if you are pregnant or breast-feeding.

High blood pressure: Licorice can raise blood pressure. Don’t consume large amounts of it if you have high blood pressure.

Heart disease: Licorice can cause the body to store water, and this can make congestive heart failure worse. Licorice can also increase the risk of irregular heartbeat. Don’t consume licorice if you have heart disease.

Hormone-sensitive conditions such as breast cancer, uterine cancer, ovarian cancer, endometriosis, or uterine fibroids: Licorice might act like estrogen in the body. If you have any condition that might be made worse by exposure to estrogen, don’t use licorice.

A muscle condition caused by nerve problems (hypertonia): Licorice can cause the level of potassium to drop in the blood. This can make hypertonia worse. Avoid licorice if you have hypertonia.

Low potassium levels in the blood (hypokalemia): Licorice can lower potassium in the blood. If your potassium is already low, licorice might make it too low. Don’t use licorice if you have this condition.

Sexual problems in men: Licorice can lower a man’s interest in sex and also worsen erectile dysfunction (ED) by lowering levels of a hormone called testosterone.

Kidney disease: Overuse of licorice could make kidney disease worse. Don’t use it.

Surgery: Licorice might interfere with blood pressure control during and after surgery. Stop taking licorice at least 2 weeks before a scheduled surgery.

Major

Moderate

Using too much licorice can decrease potassium in the body. This can damage the heart. Using licorice with herbs that can damage the heart might make this effect worse. Herbs that might damage the heart include digitalis, lily-of-the-valley, pheasant's eye, and squill.

Using too much licorice can decrease potassium in the body. Herbs that have a stimulant laxative effect can also lower potassium in the body. Using licorice along with these herbs can increase the risk of lowering potassium levels too much. Stimulant laxative herbs include aloe vera, alder buckthorn, European buckthorn, cascara sagrada, castor oil, rhubarb, and senna.

Drinking grapefruit juice when taking licorice might increase licorice's ability to cause potassium depletion.

Licorice use can increase sodium and water retention and increase blood pressure. Also, eating a lot of salt can make the side effects of licorice even worse.

The following doses have been studied in scientific research:

BY MOUTH:

• For upset stomach: A specific combination product containing licorice (Iberogast, Medical Futures, Inc) and several other herbs has been used in a dose of 1 mL three times daily.

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To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.methodology (http://www.nlm.nih.gov/medlineplus/druginfo/natural/methodology.html).

To see all references for the Licorice page, please go to http://www.nlm.nih.gov/medlineplus/druginfo/natural/881.html.

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Page last updated: 27 September 2012