A member of the pea family, licorice root has been used since ancient times both as food and as medicine. In Chinese herbology, licorice is an ingredient in nearly all herbal formulas for the traditional purpose of "harmonizing" the separate herbs involved.

The herb licorice contains a substance called glycyrrhizin. When taken in high enough amounts, glycyrrhizin produces effects similar to those of the natural hormone aldosterone, causing fluid retention, increased blood pressure, and loss of potassium. To prevent this, manufacturers have found a way to remove glycyrrhizin from licorice, producing the safer product deglycyrrhizinated licorice (DGL).

Eczema

Creams containing whole licorice (often combined with extract of chamomile) are in wide use as "natural hydrocortisone creams." However, there is only preliminary supporting evidence for this use. In one double-blind, placebo-controlled trial of 30 people, licorice gel at 2% was more effective than placebo or 1% gel for reducing symptoms of eczema.

Licorice has constituents that increase the activity of naturally occurring (or artificially supplied) corticosteroids, and this might explain some of the benefits seen. In addition, licorice contains licochalcone A, a substance hypothesized to have anti-inflammatory effects.

Ulcer Treatment

Two controlled studies suggest that regular use of DGL in a combination product also containing antacids can heal ulcers as effectively as drugs in the Zantac family. Unfortunately, these studies do not prove that DGL was effective; antacids themselves can help heal ulcers, and in any case the studies were not double-blind.

Furthermore, if it does work, DGL would have to be taken continuously to avoid ulcer recurrence. In some cases, drug treatment can prevent the recurrence of ulcers permanently by eradicating the bacteria Helicobacter pylori. There is no evidence as yet that DGL can do the same.

Ulcer Prevention

A very preliminary study suggests that DGL might help prevent ulcers caused by aspirin and related medications (such as ibuprofen).