What Is It?
Health Benefits
Dosage Information
Guidelines for Use
General Interaction
Possible Side Effects
Evidence Based Rating Scale

What Is It?

Few herbal remedies have been as widely used or as carefully examined over the centuries as licorice (Glycyrrhiza glabra), a botanical member of the pea family that is still widely cultivated in Greece and Turkey. The herb's key therapeutic compound, glycyrrhizin, is found in the rhizome (or underground stem) of this tall purple-flowered shrub. Hundreds of other potentially healing substances have been identified in licorice as well, including compounds called flavonoids and various plant estrogens (phytoestrogens). Given its long history of traditional medicinal use, researchers are confirming the diverse healing properties of licorice, from its anti-inflammatory abilities to its capacity to soothe stomach upset and control coughs. It is also being promoted as an effective treatment for prostate cancer.

Licorice is often added to herbal blends, because its distinctive, sweet taste is a good way to conceal the bitterness of the other herbs. Supplements containing therapeutic amounts of licorice come in two forms: either with glycyrrhizin or without glycyrrhizin, a form known as deglycyrrhizinated licorice, or DGL.

Health Benefits

Glycyrrhizin exerts numerous beneficial effects on the body, making licorice a valuable herb for treating a host of ailments. It can help reduce inflammation. It seems to prevent the breakdown of adrenal hormones such as cortisol (the body's primary stress-fighting adrenal hormone), making these hormones more available to the body. Licorice has been shown to enhance immunity by boosting levels of interferon, a key immune system chemical that fights off attacking viruses. Licorice root also contains powerful antioxidants, as well as certain phytoestrogens that can perform some of the functions of the body's natural estrogens.

It also protects the digestive tract from corrosive stomach acids by stimulating the production of substances that coat the stomach and esophagus. This characteristic makes it useful for a whole different group of ailments. In fact, traditional Chinese medicine commonly uses licorice to protect the digestive system from the harsher effects of other herbs.

Specifically, licorice may help to:

  • Control respiratory problems and sore throat. Licorice eases congestion and coughing by helping to loosen and thin mucus in airways; this makes a cough more "productive," bringing up phlegm and other airway waste products. Licorice also helps to relax bronchial spasms. The herb also soothes soreness in the throat and fights viruses that cause respiratory illnesses and the resulting overproduction of mucus. The German Commission E has endorsed licorice root for the treatment of coughs and bronchitis.
  • Lessen symptoms of chronic fatigue syndrome and fibromyalgia. By enhancing cortisol activity, glycyrrhizin helps to increase energy, ease stress, and reduce the symptoms of ailments sensitive to cortisol levels, such as chronic fatigue syndrome and fibromyalgia. In the 1800s, licorice extract was a common remedy for a type of persistent fatigue known as neurasthenia, the condition now known as chronic fatigue syndrome.
  • Combat hepatitis. Licorice both protects the liver and promotes healing in this vital organ. The herb's anti-inflammatory properties help calm hepatitis-associated liver inflammation. Licorice also fights the hepatitis C virus and supplies valuable antioxidant compounds that help maintain the overall health of the liver (1).
  • Soothe skin irritations such as eczema and shingles. Licorice cream applied directly to irritated skin can help to reduce inflammation and relieve such symptoms as itching and burning (2). It also boosts the effectiveness of cortisone creams.
  • Treat PMS and menstrual problems. The phytoestrogens in licorice have a mild estrogenic effect, making the herb potentially useful in easing certain symptoms of PMS (premenstrual syndrome), including irritability, bloating, and breast tenderness. Although the glycyrrhizin in licorice actually inhibits the effect of the body's own estrogens, the mild estrogenic effect produced by licorice's phytoestrogens manages to override this inhibiting action.
  • Fight cancer. Studies on licorice being used to fight breast and prostate cancer show promise. Research has demonstrated that the mild estrogenic effects of licorice components help to slow the progression of breast cancer (4,5). Other studies have shown that the bioactive compounds of licorice may be chemopreventive in other cancers, including prostate cancer (6). More research is necessary to determine the types of cancer that respond, as well as the dosage and treatment routines that respond best to licorice supplementation.
  • Alleviate ulcers, heartburn, indigestion, and inflammatory bowel problems such as Crohn's disease and ulcerative colitis. Ailments associated with the damaging effects of corrosive stomach acids respond well to treatment with chewable DGL wafers, which promote the production of substances that coat and thus protect the esophagus, stomach, and intestinal lining. Many integrative practitioners recommend licorice instead of prescription acid lowering medications. One study compared DGL tablets to cimetidine and found them just as effective at promoting healing of stomach ulcers. (7) In a study of 120 patients with dyspepsia after 4 weeks, 43.3% of people treated with an herbal preparation containing licorice reported complete relief of their symptoms (8). Other randomized controlled trials have also shown this effect (9).


  • Control canker sores. By coating and shielding these painful mouth ulcers from irritants, chewable DGL wafers can accelerate healing (10).

Note: Licorice has also been found to be useful for a number of other disorders. For information on these additional ailments, see our Dosage Recommendations Chart for Licorice.


    • wafer
    • tincture
    • tablet
    • lozenge
    • tea
    • loose dried herb
    • cream
    • capsule

Dosage Information

Special Tips:

Licorice products are manufactured in two forms – standard and “deglycyrrhizinated” (DGL). The form that is appropriate for you depends on the amount and duration of treatment and other medical conditions. Licorice that contains glycyrrhizin may reduce blood potassium levels, lead to water retention, and increase blood pressure. Although the dose of licorice that leads to these side effects is fairly large – about 10 grams of root containing at least 1 gram of glycyrrhizin for at least two weeks – if you have a history of high blood pressure or are taking medicines that decrease your potassium, it would be wise to take choose the DGL form.

For licorice with glycyrrhizin, look for products standardized to contain 22% glycyrrhizinic acid or glycyrrhizin. For licorice without glycyrrhizin, look for medications labeled DGL or "deglycyrrhizinated."

  • For most disorders: Take 200 mg standardized extract in pill form three times a day, or 20 to 45 drops of a 1:5 tincture three times a day. (The 1:5 tincture represents one part herb in five parts liquid).
  • For cough and congestion: Drink one cup of licorice tea three times a day. To make the tea, pour 8 ounces of very hot (but not boiling) water over 2 teaspoons of the herb, steep for 10 minutes, and then strain. To make a blended herbal tea for coughs, steep 1 teaspoon each of dried licorice and slippery elm in very hot (but not boiling) water along with 2 teaspoons of the herb marshmallow for 5 minutes. Drink one cup three times a day. Use no longer than three weeks.
  • For hepatitis: Take 200 mg three times a day for up to 10 days.
  • For PMS and menstrual disorders: Take 200 mg three times a day for the 10 days before you expect to start menstruating.
  • For skin irritations such as eczema and shingles: Apply licorice cream (sometimes called glycyrrhetinic acid cream) directly to the lesions three or four times a day.
  • For canker sores: Chew one or two 380-mg DGL wafers three or four times a day, between meals.
  • For heartburn: Chew two 380-mg DGL wafers three or four times a day, as needed. The wafers can safely be added to a regimen of prescription or over-the-counter heartburn medications.
  • For flare-ups of inflammatory bowel disorders such as Crohn's disease and ulcerative colitis: Chew two 380-mg DGL wafers three times a day.
  • For ulcers: Chew one or two 380-mg DGL wafers three times a day.

Be sure to check out our Dosage Recommendations Chart for Licorice, which lists therapeutic dosages for specific ailments at a glance.

Guidelines for Use

  • Take care to use licorice in the proper formulation recommended for the ailment you're treating.
  • Sore throat pain responds best to licorice in lozenge form, although warm tea can also be soothing.
  • When treating chronic fatigue syndrome, keep in mind that it may take a month for the supplements to start working.
  • Don't use licorice candy in place of supplements. Most red or black licorice candy sold in the United States contains anise oil as a flavoring rather than licorice. Candy made in Europe may contain licorice, but the quantities are not standardized.
  • DGL wafers should be chewed thoroughly about 30 minutes before a meal; the saliva activates their medicinal effects.

General Interaction

  • Don't use licorice if you take blood pressure drugs or any other substances that can alter your blood pressure; the licorice may neutralize the medication's ability to lower blood pressure. Licorice may also interfere with the blood pressure-lowering actions of digitalis drugs (digitoxin and digoxin).
  • Don't take licorice if you're on diuretics. Hazardously low potassium levels may result when licorice is combined with a regimen of thiazide diuretics or other drugs that promote fluid loss, such as chlorothiazide, hydrochlorothiazide, furosemide, or indapamide. Spironolactone, a diuretic which is used in some hormonal disorders, should not be combined with licorice.
  • Taking licorice with steroid medications such as prednisone may increase both their medicinal effects and their undesirable side effects.
  • Discuss with your doctor before combining licorice with oral contraceptives; there have been reports of breakthrough bleeding (vaginal bleeding outside the menstrual cycle) in women taking both. The combination could also worsen fluid retention in some women and theoretically could increase the risk of high blood pressure.
  • Although it's unlikely to be a problem because the phytoestrogens in licorice are so mild, some sources recommend against taking licorice in combination with hormone replacement therapy.

Note: For information on interactions with specific generic drugs, see our WholeHealthMD Drug/Nutrient Interactions Chart.

Possible Side Effects

  • Licorice can raise blood pressure--a function of glycyrrhizin's action on the adrenal glands--so avoid taking more than the recommended dosage. If you take licorice for more than four weeks, have your blood pressure checked. (Stop taking the herb at the first sign of high blood pressure; this side effect is reversible with discontinuation of the herb.)
  • At high doses taken over long periods of time, licorice can result in excessive potassium loss from the blood, heart irregularities, and other serious health problems. Symptoms of this side effect may include headache, swelling, stiffness, shortness of breath, upper abdominal pain, and lethargy, among others.
  • Side effects should disappear very shortly after stopping licorice. If they don’t, see a doctor at once.
  • No side effects have been linked to DGL use.


  • With the exception of DGL (which poses no known risk of side effects), always consult a doctor before taking licorice medicinally.
  • Have your blood pressure checked after taking licorice for a month. If it's higher than normal, discontinue the licorice and consult your doctor.
  • To minimize the risk of dangerous side effects, don't take licorice in medicinal concentrations for longer than six weeks.
  • Given its potential to increase blood pressure, avoid licorice if your blood pressure is already high or if you have glaucoma, diabetes, or diseases of the heart, liver, or kidneys. (Taking the DGL version of licorice poses no known risk in such situations.)
  • Avoid licorice if you suffer from an eating disorder; abnormally low blood concentrations of potassium might become exacerbated.
  • Licorice candy (popular in Europe), chewing tobacco, soft drinks, and over-the-counter cough medicines sometimes contain licorice. Avoid combining these products with licorice supplements because when taken together the combined effect may elevate your blood pressure or cause other problems. Even products containing small amounts of licorice can create side effects when taken in large quantities on their own.
  • Don't use licorice if you are pregnant or nursing.

Evidence Based Rating Scale

The Evidence Based Rating Scale is a tool that helps consumers translate the findings of medical research studies with what our clinical advisors have found to be efficacious in their personal practice. This tool is meant to simplify which supplements demonstrate promise in the treatment of certain conditions. This scale does not take into account any possible interactions with any medication/ condition/ or therapy which you may be currently undertaking. It is therefore advisable to ask your doctor before starting any new treatment regimen.




Date Published: 01/14/2007
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