Herpes is a viral infection caused by one of two types of the herpes simplex virus. Herpes simplex type 1 usually causes infections above the waist, while type 2 causes infections below the waist, principally on the genitals, anus and buttocks. However, either type can infect almost any site on the skin, according to National Institutes of Health researchers Dr. Adriana R. Marques and Dr. Stephen E. Straus in the 2008 edition of “Fitzpatrick’s Dermatology in General Medicine.” There is no cure for herpes, so herbs such as licorice root have attracted attention as a means of reducing the severity and duration of symptoms.


In the 2006 edition of "Natural Pharmacy," holistic medicine specialist Dr. Alan R. Gaby says that licorice root, known by the botanical names Glycyrrhiza glabra and Glycyrrhiza uralensis, has a “long and highly varied record of uses.” According to Gaby, it remains one of the most important herbs in traditional Chinese medicine, in which practitioners use it to treat viral infections such as herpes, as well as other conditions as varied as diabetes and epilepsy. Although it is commonly referred to as licorice root, that is technically a misnomer since both the root and underground stems, called rhizomes, are used in herbal remedies.


There are two types of licorice root: standard and de-glycyrrhizinated, sometimes abbreviated as DGL. People with herpes should choose standard preparation since glycyrrhizin is one of the components thought to confer therapeutic benefits for herpes. Standard licorice comes as the dried, unprocessed root, liquid extract, cream, pills or gels. People with herpes should avoid the dried, unprocessed root because the coarse particles may irritate herpes sores. All other forms can be adapted for topical use.


Patients can apply a thin layer of liquid extract, cream or gel directly to herpes sores using a cotton swab or fingertips. Pills should be crushed and mixed with an amount of water or sweet almond oil sufficient to form a thin paste. Patients can then apply the paste to herpes sores. For patients with herpes sores inside the mouth, Gaby recommends making a mouth wash of approximately 1 tbsp. of crushed licorice root pills with 1 cup of warm water. Patients should swirl a small amount inside the mouth for three or four minutes, then spit the solution into the sink. Unused solution can be covered and refrigerated for later use. Patients should use licorice three or four times per day until herpes sores heal.


Taken orally, licorice root may cause side effects such as increased blood pressure and fluid retention. However, these risks do not apply to people who use the herb topically. The major risk of topical licorice root is skin irritation. Licorice root preparations are not standardized, so even a previously tolerated form of the product can cause irritation when a new batch is purchased. People who experience irritation should discontinue use and see a doctor if symptoms persist after three days. Licorice root has not been subjected to the same studies as conventional medications for herpes, so there are no guarantees that it will be effective. Licorice root does not replace conventional medications for herpes or any other condition. People who experience frequent, severe or prolonged symptoms should see a doctor.


Licorice root contains two compounds thought to benefit herpes. Glycyrrhizin is an anti-inflammatory that quells swelling, redness and discomfort, while flavonoids in licorice extract counteract the growth of the herpes simplex virus, at least in test tubes. The net effect may be a reduction in the severity and duration of herpes symptoms. However, Gaby cautions, the use of licorice root extract for herpes is mainly based on tradition, not science. As of October 2010, the National Library of Medicine lists no clinical trials to support the effectiveness of licorice root on herpes.