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). Researchers are currently excited about the diverse healing properties of licorice, from its anti-inflammatory abilities to its capacity to soothe stomach upset and control coughs. Even the National Cancer Institute has investigated the medicinal benefits of licorice.
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.
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 also appears 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.
DGL, on the other hand, 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 uses licorice to protect the digestive system from the harsher effects of other herbs.
Specifically, licorice with glycyrrhizin 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 mucus bits. Licorice also helps to relax bronchial spasms; asthma sufferers may find they can breathe more comfortably after taking licorice. The herb also soothes soreness in the throat and fights viruses that cause respiratory illnesses and an overproduction of mucus.
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 fibromylagia. 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 virus commonly responsible for hepatitis, and supplies valuable antioxidant compounds that help maintain the overall health of the liver.
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. 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), such as 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.
Control menopausal symptoms. The phytoestrogens in licorice may help to minimize menopausal symptoms by compensating somewhat for the natural decline in a woman’s estrogen levels following menopause.
Prevent heart disease. Recent studies have found that by limiting the damage from LDL (“bad”) cholesterol, licorice may discourage artery-clogging plaque formation and contribute to the healthy functioning of the heart. Research indicates that modest doses of licorice (100 mg a day) have this effect. The ingredient responsible, glabridin, is not present in licorice candy but can be obtained through licorice root supplements and standardized extracts.
Fight cancer. Preliminary animal studies suggest that the glycyrrhizin in licorice may boost immune-system activity, helping to prevent cancers of the colon, breast, and other body parts. The herb’s phytoestrogens may also play a role in fighting breast cancer.
Deglycyrrhizinated licorice (DGL) can help to:
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. In cases of heartburn, DGL also aids in the repair of the stomach’s protective mucous lining. In a number of clinical trials, standard anti-ulcer medications failed to perform as well as DGL supplements.
Control canker sores. By coating and shielding these painful mouth ulcers from irritants, chewable DGL wafers can accelerate healing.
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.
–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, three times a day, of a 1:5 tincture. (The 1:5 tincture represents one part herb is soaked in five parts liquid).
For cough, congestion, and asthma: 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 (licorice or DGL) 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.
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. For example, licorice may 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, also should not be combined with licorice.
Taking licorice with steroid medications such as prednisone may increase both their medicinal effects and their often undesirable side effects.
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 WholeHealth Chicago 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.)
At high doses taken over long periods of time, licorice can result in excessive salt loss from the blood, heart irregularities, and other serious health problems. Symptoms of this type of overdose 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 not, see a doctor at once.
No side effects have been linked to DGL use.
With the exception of DGL (which poses no 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 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 as well. Just the 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.
Asthma 250-500 mg standardized extract 2 or 3 times a day; or 2-4 ml standardized liquid extract 2 or 3 times a day; or 1,000-2,000 mg whole root 2 or 3 times a day
Canker Sores Chew 1 or 2 380 mg deglycyrrhizinated licorice (DGL) wafers 3 or 4 times a day between meals.
Chronic Fatigue Syndrome 400-450 mg a day or 1 tsp. liquid extract a day
Cough Add 1 tsp. liquid extract to 1 cup (8 oz.) hot water 3 times a day. Alternatively, drink 1 cup licorice tea (or a licorice-containing herbal cough tea) 3 times a day.
Eczema Apply licorice cream (also called glycyrrhetinic acid cream) directly to lesions 3 or 4 times a day.
Fibromyalgia 200 mg standardized extract 3 times a day
Heartburn Chew 2-4 380 mg deglycyrrhizinated licorice (DGL) wafers 3 or 4 times a day as needed.
Hepatitis 200 mg 3 times a day for up to 10 days
PMS 200 mg standardized extract 3 times a day for the 10 days preceding your menstrual period
Shingles Apply liberal amount of cream to blistered skin 3 times a day as an alternative to melissa cream.
Ulcers Chew 2 380-mg deglycyrrhizinated licorice (DGL) wafers 3 times a day for two months.
Because it’s been used as a therapeutic herb for thousands of years and has been researched intensively as well, we know a lot more about licorice than we do about most other medicinal plants. In fact, many of the claims made in ancient medicine–mainly that licorice works for lung and stomach conditions–have been borne out by modern clinical research. In the United States, we primarily know licorice as a flavoring, which is ironic because licorice candy actually contains anise and not real licorice at all.
HOW IT HELPS ASTHMA
Ancient Greek physicians were the first to record that licorice helps coughs, colds, and asthmatic conditions. In Germany today, physicians still routinely recommend licorice in teas and syrups to control coughs. The primary medicinal component in licorice root that helps asthma is glycyrrhetinic acid (or glycyrrhizin). Like the adrenal hormone cortisol, glycyrrhetinic acid acts as an anti-inflammatory in treating asthmatic and allergic reactions.
WHAT TO LOOK FOR
There are two types of licorice available: Regular licorice, sold either as a whole root or as a standardized product. It’s usually sold as capsules, fluid extracts, or as a tea. Deglycyrrhizinated licorice (DGL), in which the glycyrrhizin has been removed, is mainly sold to treat gastritis and stomach ulcers. Don’t get the DGL form for your asthma, however, because it’s the glycyrrhizin that appears to be the key compound needed to treat respiratory inflammation.
Because of its helpfulness for respiratory problems and its sweet flavor, licorice is a frequent ingredient in various commercial herbal cough syrups.
Both standardized extracts (with 22% glycyrrhizinic acid or glycyrrhizin) and unstandardized whole-root products are available.
Here are a several pointers for using licorice effectively. Blood pressure connection. The glycyrrhetinic acid in both whole root licorice and standardized extract licorice is the key compound that helps with asthmatic/allergic symptoms. But it can also cause fluid retention and raise blood pressure in some people, although not everyone’s blood pressure goes up during licorice use. If you already have high blood pressure, kidney disease, or are using the heart medication digoxin, it’s best to avoid licorice altogether. Long-term use. Licorice should not be taken for longer than six weeks.
While taking licorice makes a lot of sense for helping to prevent inflammatory flares that can prompt an asthmatic response in your airways, don’t count on it to stop an acute asthma attack. And never substitute licorice or any other herbal remedy for a prescription asthma drug unless your doctor specifically recommends it.
David Edelberg, MD