Licorice root is often used for a variety of conditions.
Deglycyrrhizinated licorice (DGL) is often suggested as a treatment for stomach ulcers, although there's only mixed evidence about 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'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 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 found that 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 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)
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 works.
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 had 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.
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 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 health care 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)
- Erecetile dysfunction
Pregnant or breastfeeding women should not take licorice.
Don't use any licorice product for longer than 4 - 6 weeks.
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