What are the side effects of black licorice? A guide to risks and safety

December 12, 2025 •

3 min read

Excessive black licorice consumption can lead to serious health problems, a fact underscored by a 2020 case report in which a man died from related complications. Understanding the side effects of black licorice is crucial for safe consumption, particularly for individuals over 40 or those with pre-existing conditions.

Quick Summary

The health risks of black licorice are tied to the compound glycyrrhizin, which can cause high blood pressure, low potassium, and other serious cardiovascular problems when overconsumed.

Key Points

Glycyrrhizin is the Culprit: The active compound in real licorice root, glycyrrhizin, is responsible for the harmful effects, not anise oil.
Cardiovascular Health Risks: Overconsumption can lead to dangerous high blood pressure, irregular heart rhythms (arrhythmia), and heart failure.
Electrolyte Imbalance: Glycyrrhizin causes the body to lose potassium and retain sodium, leading to symptoms like swelling, fatigue, and muscle weakness.
Medication and Condition Interactions: Black licorice can interfere with critical medications for blood pressure and heart conditions and should be avoided by pregnant women and those with heart, kidney, or hormone-sensitive conditions.
Moderation is Key: The FDA advises that those over 40 should avoid consuming more than two ounces of black licorice per day for at least two weeks to prevent health problems.
DGL is a Safer Alternative: Deglycyrrhizinated licorice (DGL) has the glycyrrhizin removed, offering a way to consume licorice for health purposes with less risk.

The Root Cause: Glycyrrhizin

Black licorice's distinctive flavor comes from glycyrrhizin, found in the licorice plant root (Glycyrrhiza glabra). Excessive intake of glycyrrhizin causes adverse health effects. Glycyrrhizin converts to glycyrrhetinic acid, which inhibits the enzyme 11-beta-hydroxysteroid dehydrogenase type 2 (11β-HSD2). This enzyme regulates cortisol in the kidneys. Inhibiting 11β-HSD2 leads to pseudohyperaldosteronism, causing sodium and water retention and potassium excretion.

Cardiovascular Risks

High Blood Pressure (Hypertension)

Overconsumption of black licorice frequently leads to increased blood pressure. The inhibition of 11β-HSD2 increases blood volume, raising blood pressure, which is particularly dangerous for those with existing hypertension.

Irregular Heart Rhythm (Arrhythmia)

Glycyrrhizin causes potassium loss and can lead to dangerously low potassium levels (hypokalemia). Low potassium disrupts the heart's electrical system, causing arrhythmias. A fatal case of cardiac arrest linked to black licorice and low potassium was reported in 2020.

Congestive Heart Failure

Fluid and sodium retention from glycyrrhizin can worsen existing heart conditions by straining the heart. The FDA advises caution for individuals over 40.

Electrolyte Imbalance and Other Symptoms

Low Potassium (Hypokalemia)

Potassium depletion is a key side effect, causing muscle weakness, fatigue, and pain. Severe cases can result in temporary paralysis.

Edema (Swelling)

Sodium retention from glycyrrhizin leads to fluid retention and swelling, often in the ankles and feet.

Sexual Dysfunction

High black licorice intake might lower testosterone, potentially decreasing libido and worsening erectile dysfunction in men.

Drug and Health Condition Interactions

Black licorice can interact negatively with medications. Avoid if taking:

Diuretics and Heart Failure Medications: Licorice can dangerously amplify potassium loss caused by these drugs.
Warfarin: It can interfere with this blood-thinning drug, increasing clotting risk.
Corticosteroids: Licorice may increase their effects and side effects.
Hormone-Sensitive Conditions: Licorice has estrogen-like effects, concerning for conditions like breast cancer or endometriosis.
Kidney Disease: Individuals with kidney disease are more susceptible to adverse effects as they process glycyrrhizin less effectively.

Safe Consumption Guidelines

Small, occasional amounts of black licorice are generally safe for most healthy adults. The risk comes with consistent large intake. Many U.S. licorice-flavored products use anise oil and do not contain real licorice root or glycyrrhizin. Check ingredient labels for licorice extract or glycyrrhizic acid.

Tips for safe consumption:

Read the label: Confirm the presence of licorice root extract vs. anise oil.
Know the limits: Those over 40 should not eat more than two ounces daily for two weeks.
Prioritize moderation: Treat it as an occasional treat, especially if in an at-risk group.
Monitor symptoms: Stop and seek medical help if experiencing muscle weakness, swelling, or irregular heart rhythm after consumption.

Black Licorice vs. Red Licorice: A Key Difference


Feature	Black Licorice	Red Licorice
Main Flavoring	Real licorice root extract (Glycyrrhiza glabra) or anise oil.	Usually fruit-flavored (e.g., strawberry, cherry) with artificial flavorings.
Contains Glycyrrhizin?	Yes, if it contains real licorice root extract.	No.
Associated Health Risks	Potential for high blood pressure, low potassium, and heart issues with excessive intake.	No glycyrrhizin-related risks, though high sugar content poses other health concerns.
Ingredient Check	Essential to check for licorice extract or glycyrrhizic acid.	No need to check for licorice-related compounds.

Understanding Deglycyrrhizinated Licorice (DGL)

For digestive benefits without glycyrrhizin risks, deglycyrrhizinated licorice (DGL) is an option. Glycyrrhizin is removed from DGL products, making them safer for consistent use. DGL is used for conditions like heartburn and ulcers.

Conclusion

Occasional black licorice is generally safe, but excessive intake carries significant risks. Glycyrrhizin can cause electrolyte imbalance and cardiovascular issues. Monitor intake, be aware of health conditions, and consult a doctor about medication interactions. Anise oil flavored products or DGL are safer alternatives.

For more information, see the U.S. Food and Drug Administration's consumer updates.

Frequently Asked Questions

Yes, for most healthy individuals, a small amount of black licorice consumed on an occasional basis is generally considered safe. The health risks are primarily associated with excessive and prolonged consumption.

The U.S. Food and Drug Administration advises that if you are 40 or older, eating two ounces or more of black licorice daily for at least two weeks could lead to health problems like irregular heart rhythms.

The main compound is glycyrrhizin, a sweetening agent derived from the licorice root (Glycyrrhiza glabra). Excessive intake of this compound is what leads to the most serious health issues.

Black licorice contains glycyrrhizin, which can cause the body to retain sodium and water. This increases blood volume and, in turn, can significantly raise blood pressure, a condition known as pseudohyperaldosteronism.

True black licorice contains extract from the licorice root and its active compound, glycyrrhizin. Conversely, most red 'licorice' is actually candy made with fruit flavoring and artificial ingredients, containing no real licorice root or glycyrrhizin.

DGL stands for deglycyrrhizinated licorice, a form of licorice root with most of the glycyrrhizin removed. This makes it a safer alternative for those seeking the potential health benefits of licorice, particularly for digestive issues, without the risk of high blood pressure or other side effects.

Yes, black licorice can interact with certain medications, including blood thinners like warfarin, diuretics, and some blood pressure drugs. It is crucial to consult a healthcare professional about potential interactions.

People with existing heart or kidney disease, high blood pressure, pregnant women, and anyone taking medication for heart conditions or fluid retention should be particularly cautious or avoid black licorice altogether.