The root of the licorice plant is used in complementary and alternative medicine. There are two types of licorice supplements -- those made with the whole licorice root and those made with deglycyrrhizinated licorice, or DGL, which has had the substance glycyrrhiza removed to minimize side effects from using licorice.
Licorice may help to soothe sore throats and may help to expel mucous and phlegm. It also may help reduce the symptoms of peptic ulcers, according to the University of Maryland Medical Center. Topical applications of licorice may help relieve eczema symptoms. However, the evidence to support the use of licorice for these and other uses is preliminary and contradictory.
The highest safe dosage for long-term use of licorice is .3 g per day, according to Baptist Health Systems. Higher doses should only be used for one week unless you are under the supervision of a doctor. For treatment of ulcers, the usual dose for adults is between two and four 380 mg tablets of DGL taken in the morning and at bedtime or .4 to 1.6 g of DGL extract taken three times per day.
Whole licorice can cause side effects including fatigue, high blood pressure, headaches, water retention, numbness, muscle pain, low levels of potassium and heart attacks. Side effects are more common at high doses or with long term use. Whole licorice also lowers testosterone levels in men and may decrease blood sugar levels. DGL is less likely to cause side effects.
Pregnant women shouldn't take licorice supplements because it may increase preterm labor risk. If you have heart, liver or kidney problems, diabetes, high blood pressure or problems with fluid retention you should also avoid taking these supplements. Licorice can interact with certain medications, including diuretics, ACE inhibitors, corticosteroids, laxatives, diabetes medications, oral contraceptives, MAO inhibitors, steroids, blood pressure medications, hormone therapy and digoxin.