The use of herbs is a time honored approach to strengthening the body and treating disease. Herbs, however, contain components that can trigger side effects and that can interact with other herbs, supplements, or medications. For these reasons, you should take herbs with care, preferably under the supervision of a health care provider in the field of botanical medicine.
Licorice with glycyrrhizin may cause serious side effects. Too much glycyrrhizin causes a condition called pseudoaldosteronism, which can cause a person to become overly sensitive to a hormone in the adrenal cortex. This condition can lead to headaches, fatigue, high blood pressure, and even heart attacks. It may also cause water retention, which can lead to leg swelling and other problems.
Although the most dangerous effects generally only occur with high doses of licorice or glycyrrhizin, side effects may occur even with average amounts of licorice. Some people experience muscle pain or numbness in the arms and legs. To be safe, ask your health care provider to monitor your use of licorice.
People with the following conditions should not take licorice:
- Heart failure
- Heart disease
- Fluid retention
- High blood pressure (hypertension)
- Kidney disease
- Liver disease
Pregnant or breastfeeding women should not take licorice.
Use of any licorice product is not recommended for longer than 4 - 6 weeks.
If you are currently being treated with any of the following medications, you should not use licorice without first talking to your doctor:
Ace inhibitors and diuretics -- If you are taking angiotensin converting enzyme (ACE) inhibitors or diuretics for high blood pressure, do not use licorice products. Licorice could interfere with the effectiveness of these medications or could worsen possible side effects. ACE inhibitors include:
- Captopril (Capoten)
- Benazepril (Lotensin)
- Enalapril (Vasotec)
- Lisinopril (Prinivil, Zestril)
- Gosinopril (Monopril)
- Ramipril (Altace)
- Perindopril (Aceon)
- Quinapril (Accupril)
- Moexipril (Univasc)
- Trandolapril (Mavik)
- Digoxin -- Because licorice may dangerously increase the risk of toxic effects from digoxin, this herb should not be taken with this medication.
- Corticosteroids -- Licorice may increase the effects of corticosteroid medications. Talk to your doctor before using licorice with any corticosteroids.
- Insulin or drugs for diabetes -- Licorice may have an effect on blood sugar levels.
- Laxatives -- Licorice may cause potassium loss in people taking stimulant laxatives.
- MAO inhibitors -- Licorice may make the effects of this class of antidepressant stronger.
- Oral contraceptives -- There have been reports of women developing high blood pressure and low potassium levels when they took licorice while on oral contraceptives.
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Alternative NamesGlycyrrhiza glabra; Spanish licorice; Sweet root
Licorice (Glycyrrhiza glabra) is a flavorful herb that has been used in food and medicinal remedies for thousands of years. Also known as "sweet root," licorice root contains a compound that is about 50 times sweeter than sugar. Licorice root has been used in both Eastern and Western medicine to treat a variety of illnesses ranging from the common cold to liver disease. This herb has long been valued as a demulcent (soothing, coating agent) and expectorant (rids phlegm and mucous from the respiratory tract). It is still used today for a variety of conditions, although not all its uses are supported by scientific evidence.
Licorice with the active ingredient of glycyrrhiza can have serious side effects. Another type of licorice, called DGL (deglycyrrhizinated licorice), doesn't seem to have the same side effects and is sometimes used to treat peptic ulcers, canker sores, and reflux (GERD). Whole licorice is still sometimes suggested for cough, asthma, and other respiratory problems. Topical preparations are used for eczema and other skin problems.
Licorice grows wild in some parts of Europe and Asia. A perennial that grows 3 - 7 feet high, licorice has an extensive branching root system. The roots are straight pieces of wrinkled, fibrous wood, which are long and cylindrical (round) and grow horizontally underground. Licorice roots are brown on the outside and yellow on the inside. Licorice supplements are made from the roots and underground stems of the plant.
Medicinal Uses and Indications
Licorice root is often used for a variety of conditions.
Deglycyrrhizinated licorice (DGL) is often suggested as a treatment for stomach ulcers, although evidence as to whether it works is mixed. A few studies have found that DGL and antacids helped treat ulcers as well as some prescription drugs. However, since antacids were combined with DGL, it's not possible to know how much of the benefit came from DGL alone. One animal study found that aspirin coated with licorice reduced the number of ulcers in rats by 50%. (High doses of aspirin often cause ulcers in rats.) In one study, licorice root fluid extract was used to treat 100 patients with stomach ulcers (86 of whom had not improved with conventional medication) for 6 weeks. Ulcers disappeared in 22 of these patients; 90% of participants improved. Other studies have found that DGL had no effect on peptic ulcers in humans.
Canker sores (Apthous ulcers)
One small study found that the majority of people with canker sores who gargled 4 times per day with DGL dissolved in warm water found pain relief.
In one study, licorice gel, applied topically, helped relieve symptoms of itching, swelling, and redness. A gel with 2% licorice was more effective than a gel with 1% licorice.
Dyspepsia (indigestion, GERD)
Some preliminary studies suggest that a specific herbal formula containing licorice, called Iberogast or STW 5, may help relieve symptoms of indigestion or GERD. This herbal formula also contains peppermint and chamomile, two herbs often used for indigestion.
Upper respiratory infections (cold, cough)
Licorice is a traditional treatment for cough and asthma. Studies have shown mixed results as to whether it is effective.
One human study found that a preparation of licorice may reduce body fat. Fifteen people of normal weight consumed licorice for 2 months (3.5 g a day). Body fat was measured before and after treatment. Licorice appeared to reduce body fat mass and to suppress the hormone aldosterone; however, participants retained more water. Another study found that a topical preparation of glycyrrhetinic acid (a component of licorice) was able to reduce the thickness of fat on the thigh in human subjects. A third study found that people who took 900 mg of licorice flavonoid oil daily for 8 weeks experienced significant decreases in body fat, body weight, body mass index, and LDL cholesterol levels. More studies are needed to say if licorice really helps reduce fat. In addition, taking licorice long term has a number of health risks.
People who regularly take large amounts of licorice (more than 20 g/day) may raise blood levels of the hormone aldosterone, which can cause serious side effects, including headache, high blood pressure, and heart problems. For people who already have high blood pressure or heart or kidney disease, as little as 5 g/day can cause these side effects. Further studies are needed.
Licorice products are made from peeled and unpeeled dried root. There are powdered and finely cut root preparations made for teas, tablets, and capsules, as well as liquid extracts. Some licorice extracts do not contain glycyrrhizin. These extracts are known as deglycyrrhizinated licorice (DGL), and do not seem to have the undesired side effects of other forms of licorice. Some studies suggest DGL may be better for stomach or duodenal ulcers. DGL may offer protection against ulcer formation when taken with aspirin.
How to Take It
Older children who have a sore throat can chew a piece of licorice root or drink licorice tea. The appropriate dose of tea for a child should be determined by adjusting the recommended adult dose to account for the child's weight. Most herbal dosages for adults are calculated on the basis of a 150 lb (70 kg) adult. Therefore, if the child weighs 50 lb (20 - 25 kg), the appropriate dose of licorice would be 1/3 of the adult dosage. Don't give a child licorice tea for more than a day without talking to your doctor. Never give any licorice tea to an infant or toddler.
Licorice can be taken in the following forms:
- Dried root: 1 - 5 g as an infusion or decoction (boiled), 3 times daily
- Licorice 1:5 tincture: 2 - 5 mL, 3 times daily
- Standardized extract: 250 - 500 mg, 3 times daily, standardized to contain 20% glycyrrhizinic acid
- DGL extract: 0.4 - 1.6 g, 3 times daily, for peptic ulcer
- DGL extract 4:1: chew 300 - 400 mg, 3 times daily 20 minutes before meals, for peptic ulcer
Don't use these doses of licorice for longer than a week without talking to your doctor, because of the risk of potentially dangerous side effects.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. ©1997-2013 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
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