Mention the word licorice, and most people think of the chewy black candy that they have been eating since they were kids. But licorice is also a potent herb that has been used since ancient times for medicinal purposes.
Licorice root comes from a purple and white flowering perennial that originated in the Mediterranean region and central and southwest Asia. Traditionally, it has been boiled to extract its sweetness and has been used in making licorice candy. But licorice root, by itself or in compounds with other herbs, has many medicinal uses.
Licorice root contains glycyrrhizin, a substance that can cause fluid retention, increased blood pressure, and loss of potassium when taken in large amounts or in moderate amounts for 2 weeks or more. To prevent this effect, some manufacturers remove glycyrrhizin from the licorice root, to produce a licorice-related product called deglycyrrhizinated licorice (DGL).
Proposed Uses of Licorice
Gastric ulcers and stomach irritation —Weak evidence suggests that DGL might help protect the stomach from the irritation and ulcers caused by nonsteroidal anti-inflammatory drugs (NSAIDs). DGL has not been proven to eradicate bacteria-related ulcers, which require standard medical treatment.
Mouth sores —DGL might help relieve the discomfort of canker sores in the mouth, although there have not been any studies on this subject.
Eczema, psoriasis, and herpes —A topical licorice cream (often mixed with chamomile extract) is sometimes used to treat various skin conditions, such as eczema, psoriasis, and herpes, but there is little evidence for its effectiveness in treating eczema.
Dosage and Safety Issues
For ulcer treatment not related to a bacterial infection, the standard dose of DGL is 2-4 380 mg tablets taken before meals and at bedtime. For mouth pain, the tablets can be slowly dissolved in the mouth.
The standard dose of whole licorice is 5-15 grams per day. However, you should not use doses this high for more than a few weeks. Excessive use of licorice (not DGL) may increase blood pressure and cause fluid retention, headache, and loss of potassium.
A maximum adult dose of 0.3 grams of licorice root per day has been recommended by experts for long-term use. Larger doses should only be taken under the supervision of your doctor.
Licorice is also available in a liquid form.
Whole licorice reduces testosterone in men, and therefore may adversely affect fertility or libido. Licorice use should be avoided by women who are pregnant or nursing, or who have had breast cancer.
When taken with thiazide diuretic medication, licorice may increase potassium loss. Sensitivity to digitalis glycosides may occur with loss of potassium. Licorice should not be taken with the following medications:
- Cardiac glycosides (such as digoxin)
- Diuretics
- Steroids
- Any potassium-depleting drugs
- Antihypertnesive drugs
If you are considering taking licorice root or DGL, talk to your doctor first to rule out potential drug interactions or other concerns.
RESOURCES
National Center for Complementary and Alternative Medicine http://www.nccam.nih.gov
Office of Dietary Supplements—National Institutes of Health http://ods.od.nih.gov
CANADIAN RESOURCES
Canadian Pharmacists Association www.pharmacists.ca
Health Canada http://www.hc-sc.gc.ca
References
Licorice. EBSCO Natural and Alternative Treatments website. Available at: http://www.ebscohost.com/biomedical-libraries/natural-alternative-treatments. Updated August 2013. Accessed July 15, 2016.
Licorice root. National Center for Complementary and Alternative Medicine website. Available at: http://nccam.nih.gov/health/licoriceroot. Updated April 2012. Accessed July 15, 2016.