Licorice root is used for a variety of conditions.
DGL is often suggested as a treatment for stomach ulcers, although it is not clear whether it works. 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 is 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 people with stomach ulcers, 86 of whom had not improved with conventional medication, for 6 weeks. Ulcers disappeared in 22 people; 90% of participants got better. Other studies have found that DGL had no effect on peptic ulcers in humans.
Canker sores (Apthous ulcers)
One small study suggested that gargling with DGL dissolved in warm water 4 times per day helped reduce pain among people with canker sores.
In one study, licorice gel, applied to the skin, helped relieve symptoms of itching, swelling, and redness. A gel with 2% licorice worked better than a gel with 1% licorice.
Dyspepsia (indigestion, GERD)
Preliminary studies suggest that a specific herbal formula containing licorice, called Iberogast or STW 5, may help relieve symptoms of indigestion or gastroesophageal reflux disease (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, asthma, and sore throat. One study found that gargling with licorice before getting anesthesia cut the incidence of postoperative sore throat by half.
One study found that a preparation of licorice may reduce body fat. Fifteen people of normal weight consumed 3.5 g of licorice each day for 2 months. Body fat was measured before and after treatment. Licorice appeared to reduce body fat mass and to suppress the hormone aldosterone; however, the people in the study retained more water.
Another study found that a topical preparation of glycyrrhetinic acid (a component of licorice) reduced 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 reductions 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.
Preliminary research suggests licorice may be effective at reducing hot flashes. One study found that licoricee seems more effective than HRT in improving hot flash duration.
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. More research is needed.
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, 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 dangerous effects mostly happen with high doses of licorice or glycyrrhizin, smaller amounts of licorice may cause side effects. Some people have muscle pain or numbness in the arms and legs. To be safe, ask your provider to monitor your use of licorice.
People with the following conditions should not take licorice:
- Heart failure
- Heart disease
- Hormone-sensitive cancers, such as breast, ovarian, uterine, or prostate cancer
- Fluid retention
- High blood pressure (hypertension)
- Kidney disease
- Liver disease
- Low potassium (hypokalemia)
- Erectile dysfunction
Pregnant or breastfeeding women should not take licorice. Some studies suggest that taking licorice during pregnancy can increase the risk of stillbirth.
DO NOT use any licorice product for longer than 4 to 6 weeks.
Licorice may interfere with several medications, including the ones listed below. If you are taking any medication, ask your doctor before taking licorice.
ACE inhibitors and diuretics. If you are taking angiotensin converting enzyme (ACE) inhibitors or diuretics for high blood pressure, you should not use licorice products. Licorice could cause these medications to not work as well, or could make side effects worse, including a build up of potassium in the body. 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, do not take this herb 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.
Warfarin (Coumadin). Licorice may decrease the levels of this blood thinner in the body, meaning it may not work as well.
Medications processed by the liver. Licorice may interfere with several medications processed by the liver, including celecoxib (Celebrex), diclofenac (Voltaren), fluvastatin (Lescol), glipizide (Glucotrol), ibuprofen (Advil, Motrin), phenytoin (Dilantin), piroxicam (Feldene), phenobarbital, and secobarbital (Seconal).
Diuretics, hormonal medications, and many other medications interact with licorice.
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