Overview

Licorice is made from the roots of Glycyrrhiza plants. It is found in teas, lozenges, chewables, supplements, and candies. It is also used to flavor many different foods, drinks, and tobacco products. Although licorice is used for various reasons, its benefits are not well defined. Common side effects include increased blood pressure, fluid retention, diarrhea, or loose stools. When licorice is taken in very high doses, these side effects may cause serious health problems. Most of these side effects are caused by glycyrrhizin, the chemical that gives licorice its distinct flavor. To reduce the risk of side effects, glycyrrhizin is removed from some products (deglycyrrhizinated licorice, or DGL). Before taking licorice, make sure to tell your health care provider about any health conditions you have or medicines you are taking.

Uses

What is licorice used for?

Licorice (Glycyrrhiza glabra or Glycyrrhiza uralensis) is used for many different reasons, but its benefits are not well defined. Some common reasons that people use licorice include the following.

• Acid reflux or indigestion
• Canker sores
• Constipation
• Cough or sore throat
• Wound healing

Note: The FDA has not reviewed licorice for safety and effectiveness. Learn more about dietary supplements here. When licorice is used to flavor foods, drinks, and other products, it is generally recognized as safe (GRAS) by the FDA. Learn more about GRAS status here.

How does licorice work (mechanism of action)?

Licorice is made from the roots of plants called Glycyrrhiza glabra and Glycyrrhiza uralensis. The most common form of licorice in the United States is G. glabra. Licorice also has a long history of use in the traditional medicine system in China, where G. uralensis (Chinese licorice) is known as gan zao.

Licorice contains a chemical called glycyrrhizin. This chemical has many different effects in the body and is also responsible for the strong, distinctive flavor of licorice. Although other plants, such as star anise, anise, and fennel, may be known for their licorice-like flavor, they do not contain glycyrrhizin. Instead, they contain a chemical with a licorice-like flavor, called anethole. Most foods and candies that taste like licorice are actually flavored with anethole or anise oil instead of licorice.

Glycyrrhizin can have effects that are similar to medicines known as mineralocorticoids, such as fludrocortisone. This means that it can lower your potassium levels and increase your sodium levels by binding to certain receptors in your kidneys. When large amounts of glycyrrhizin are taken by mouth, it can cause serious health problems. To address this, some licorice products do not contain glycyrrhizin. These are known as deglycyrrhizinated licorice (DGL) products.

Other chemicals in licorice, including chalcones and flavonoids, also have effects in the body. These effects may include acting as antioxidants and reducing swelling (inflammation). This activity is thought to be helpful when licorice lozenges or teas are used for acid reflux, indigestion, cough, and sore throat. However, it is not clear if licorice is helpful for relieving these symptoms. Certain chemicals in licorice may also act as laxatives, which may help to relieve mild constipation. Although there is interest in using licorice for many other reasons, including canker sores and wound healing, its benefits are not well defined.

Herbal products like licorice naturally contain many different chemicals. The amounts of each chemical in a specific licorice product may vary. Some, none, or all of these chemicals may have effects on the body. These effects may change depending on how much of each chemical is found in the product you are using.

How should I store licorice?

You should store licorice according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and not in direct sunlight.

Side Effects

What are the most common side effects of licorice?

The most common side effects of licorice are listed below. These side effects may vary depending on the specific product you are using and may be more likely with higher doses. Tell your health care provider if you have any of these side effects that bother you.

• Diarrhea or loose stools
• Increased blood pressure (see below)
• Fluid retention (see below)

There may be other side effects of licorice that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of licorice?

While less common, the most serious side effects of licorice are described below, along with what to do if they happen.

Severe Allergic Reactions. Licorice may cause allergic reactions, which can be serious. Stop using licorice and get help right away if you have any of the following symptoms of a serious allergic reaction.

• Breathing problems or wheezing
• Racing heart
• Fever or general ill feeling
• Swollen lymph nodes
• Swelling of the face, lips, mouth, tongue, or throat
• Trouble swallowing or throat tightness
• Itching or skin rash
• Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
• Nausea or vomiting
• Dizziness, feeling lightheaded, or fainting
• Stomach cramps
• Joint pain

Low Potassium Levels (Hypokalemia). Large amounts of glycyrrhizin, a chemical found in licorice, can cause a low potassium level, which can be serious and may lead to death. This may be more likely in people who are taking certain medicines or who have certain health conditions. Deglycyrrhizinated licorice (DGL) products, which do not contain glycyrrhizin, do not have this effect. Call your health care provider if you have any of the following symptoms of a low potassium level.

• Weakness
• Unusual tiredness
• Muscle cramps or twitching
• Constipation

High Sodium Levels (Hypernatremia).Large amounts of glycyrrhizin, a chemical found in licorice, can cause a high sodium level, which can be serious and may lead to death. This may be more likely in people who have kidney problems, eat a diet high in salt, or take certain medicines. Deglycyrrhizinated licorice (DGL) products, which do not contain glycyrrhizin, do not have this effect. Call your health care provider if you have any of the following symptoms of a high sodium level.

• Extreme thirst
• Confusion or irritability
• Rapid heartbeat
• Seizures

Fluid Retention (Edema).Large amounts of glycyrrhizin, a chemical found in licorice, can cause fluid retention, also called edema. Fluid retention can cause serious issues in people with certain conditions, such as heart failure or kidney problems. Deglycyrrhizinated licorice (DGL) products, which do not contain glycyrrhizin, do not have this effect. Call your health care provider right away if you have any of the following symptoms.

• Chest pain
• Irregular heartbeat
• Shortness of breath
• Stretched or shiny skin
• Swollen body parts, such as the belly or ankles

Increased Blood Pressure (Hypertension). Large amounts of glycyrrhizin, a chemical found in licorice, may increase your blood pressure or make it worse if you have a history of high blood pressure. Deglycyrrhizinated licorice (DGL) products, which do not contain glycyrrhizin, do not have this effect. Call your health care provider if your blood pressure increases while taking licorice.

If you measure your blood pressure and the top number (systolic) is 180 or higher or the bottom number (diastolic) is 120 or higher, get medical attention right away. Increases in blood pressure may not be noticeable, but look out for and tell your health care provider right away if you have any of the following symptoms of severely high blood pressure.

• Sudden severe headache
• Chest pain
• Dizziness or confusion
• Trouble breathing
• Nausea or vomiting
• Blurry or other changes to vision
• Anxiety
• Buzzing in the ears
• Nosebleed
• Feeling of skipped heartbeats

Precautions

Who should not use licorice?

Allergies to Ingredients. People who are allergic to any of the following should not use licorice.

• Gan zao
• Glycyrrhiza species
• Glycyrrhizin
• Licorice
• Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific licorice products they stock.

What should I know about licorice before using it?

Licorice cannot be marketed to treat or cure a disease.

Read and follow the directions on the specific product you are using, or use it as recommended by your health care provider.

Keep licorice out of the reach of children.

Licorice contains a chemical called glycyrrhizin. High doses of this chemical can cause serious health problems (see the Side Effects section for more details). Most reports of serious health problems related to licorice have happened in people who consume very large amounts of licorice candies, teas, or supplements on a regular basis. To help reduce the risk of serious health problems, some licorice supplements do not contain glycyrrhizin. These are known as deglycyrrhizinated licorice (DGL) products. Read the product label closely to see which form of licorice it contains.

Herbal products, such as licorice, naturally contain many different chemicals. The amount of each chemical in a specific licorice product can change for many reasons, including the area where the plant was grown, the weather during growth, the time of year when it was harvested, and the way the plant was processed after being harvested. If you switch to a new bottle or a different brand, you may not have the same effects or side effects because of this variability. Talk to your health care provider if you have questions or concerns.

Licorice is available as a dietary supplement and in many different forms, including as a tea, liquid extract, lozenge, chewable, dried ground powder found in capsules, and more. It is also added to many foods, candies, drinks, and tobacco products for flavor. Each of these forms may contain different amounts of the chemicals naturally found in the plant.

The FDA has not tested licorice products to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.

What should I tell my health care provider before using licorice?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if licorice is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions.Tell your health care provider if you have any of the following.

• Abnormal heart rhythm
• Heart problems
• High blood pressure
• Kidney problems
• High sodium levels, or eat a diet high in salt
• Low potassium levels
• Low testosterone levels

Other Medicines and Supplements.Licorice may interact with other medicines and supplements. Before taking licorice, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. There is some concern that licorice may cause early labor. Tell your health care provider if you are pregnant or plan to become pregnant.

Breastfeeding. Licorice passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed.

Interactions

Does licorice interact with foods or drinks?

There are no known interactions between licorice and foods or drinks.

It is unknown if drinking alcohol will affect licorice.

Does licorice interact with medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking licorice.

• A corticosteroid, such as dexamethasone, fludrocortisone, methylprednisolone, or prednisone, which is a medicine for certain inflammatory conditions or adrenal gland problems
• A diuretic, also called a water pill, which is a medicine used to reduce edema (fluid retention) and blood pressure
• A medicine for high blood pressure
• A stimulant laxative, such as bisacodyl or senna, which is a medicine used to treat constipation
• Digoxin (Lanoxin), which is a medicine used to treat irregular heartbeat and some types of heart failure
• Testosterone, which is a hormone used to treat low testosterone levels caused by certain conditions

Licorice may alter the blood levels of many medicines. Tell your health care provider about all medicines that you take or have recently taken.

The interactions between licorice and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with licorice is incomplete. Always check with your health care provider before taking licorice with any medicines.

Dosing

What should I do if I accidentally use too much licorice?

If you or someone else has used too much licorice, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

Many different products contain licorice, including teas, supplements, and candies. It is also used to flavor many foods, drinks, and tobacco products. Read the product label closely and speak to a health care provider about how to take licorice safely. Do not take double or extra doses, even if you miss a dose.