What is the toxic ingredient in licorice?

December 12, 2025 •

3 min read

The U.S. Food and Drug Administration (FDA) indicates that consuming over two ounces of black licorice daily for more than two weeks could be risky for individuals over 40. This is due to glycyrrhizin, the toxic component within licorice, which may lead to severe health complications if taken excessively.

Quick Summary

Glycyrrhizin, a natural compound, gives licorice its sweetness, but it can be toxic in large amounts. This can lead to electrolyte imbalances, potentially causing elevated blood pressure, irregular heartbeats, and other serious health problems.

Key Points

Glycyrrhizin is the key toxic compound: High levels of this substance, found in genuine licorice root, may lead to adverse health effects.
Causes electrolyte imbalance: Glycyrrhizin interferes with the body's sodium and potassium balance, which can cause high blood pressure and low potassium (hypokalemia).
Can lead to serious health issues: Overconsumption has been associated with irregular heart rhythms, muscle weakness, and, in severe cases, cardiac arrest.
Not all licorice is dangerous: Many candies with a licorice flavor, particularly red licorice, use anise oil, not glycyrrhizin.
DGL is a safe alternative: Deglycyrrhizinated licorice (DGL) is processed to remove most of the toxic compound, making it suitable for supplements.
Moderation is essential: Consuming small amounts is generally safe, but individuals with pre-existing heart or kidney problems should be particularly cautious.

What is Glycyrrhizin?

Glycyrrhizin, also referred to as glycyrrhizic acid, is derived from the root of the licorice plant (Glycyrrhiza glabra). This natural substance contributes to licorice's sweet taste, with a sweetness level significantly higher than sucrose. Though used in food flavoring and traditional medicine, caution is needed with prolonged high doses. The compound becomes toxic when the body converts glycyrrhizin into glycyrrhetinic acid.

How Glycyrrhizin Affects the Body

High amounts of glycyrrhizin disrupt the enzyme 11-beta-hydroxysteroid dehydrogenase type 2 (11-ßHSD2), which controls cortisol levels. Glycyrrhizin inhibits this enzyme, preventing cortisol from converting to cortisone, thereby increasing cortisol in the kidneys.

This process results in pseudohyperaldosteronism, mimicking high aldosterone levels. The body then retains sodium while excreting potassium, which can cause a hazardous electrolyte imbalance. This is particularly dangerous for those with heart or kidney issues.

Health Risks Associated with Excessive Licorice Intake

Excessive glycyrrhizin consumption may lead to various health problems, including:

High blood pressure (hypertension): Caused by sodium and water retention.
Low potassium levels (hypokalemia): Which can result in muscle weakness, fatigue, and paralysis.
Cardiac issues: Electrolyte imbalance can cause irregular heart rhythms or cardiac arrest.
Edema: Water retention causing swelling.
Weight gain: Due to fluid retention.

Real Licorice vs. Licorice-Flavored Products

Many licorice-flavored candies, such as red licorice, use anise oil and do not contain glycyrrhizin. Conversely, genuine black licorice, certain teas, and some supplements contain licorice root extract, which includes glycyrrhizin. Always check the ingredient list.

Deglycyrrhizinated Licorice (DGL)

Deglycyrrhizinated licorice (DGL) has had most of its glycyrrhizin removed, making it a safer option for those worried about toxicity. DGL is often used in supplements for conditions like stomach ulcers.

The Importance of Moderation

Toxic effects are usually the result of chronic, excessive intake of genuine licorice. Small amounts are unlikely to harm healthy adults. Individuals over 40 and those with existing health conditions should exercise caution or avoid real licorice. Consulting a doctor is advised, especially with existing health issues. A review of risks and cases is available from the National Institutes of Health.


Feature	Genuine Black Licorice (with Glycyrrhizin)	Anise-Flavored Candy (e.g., Red Licorice)
Source	Licorice root extract (Glycyrrhiza glabra)	Anise oil or other artificial flavorings
Potentially Toxic Ingredient	Glycyrrhizin	None
Associated Health Risks	High blood pressure, hypokalemia, arrhythmias with excessive intake	No similar risks associated with flavorant
Flavor Profile	Earthy, complex sweetness, often salty or bitter	More straightforward, often fruity (cherry, strawberry)
Primary Use	Candy, herbal remedies, tobacco flavoring	Confectionery
Who Should be Cautious	People with heart conditions, high blood pressure, pregnant individuals	No specific contraindications based on flavorant alone

Conclusion

In summary, glycyrrhizin is the toxic ingredient found in licorice root. While it contributes to the sweet taste, prolonged and excessive consumption can cause serious health issues, such as elevated blood pressure and electrolyte imbalances. Recognizing whether a product contains actual licorice or just flavoring and practicing moderation are essential for safe consumption. DGL provides a safer option for those who need to avoid glycyrrhizin. Always consult a healthcare professional if you have any underlying health conditions.

Frequently Asked Questions

Glycyrrhizin, a natural compound found in the root of the licorice plant (Glycyrrhiza glabra), is the toxic ingredient in licorice.

The U.S. FDA suggests that consuming more than two ounces of black licorice daily for at least two weeks could be problematic for those over the age of 40. The precise toxic dose varies based on individual health factors.

Excessive intake of glycyrrhizin may lead to high blood pressure, low potassium levels (hypokalemia), irregular heartbeat, swelling, and muscle weakness.

No, the red licorice candy often sold in the United States is flavored using anise oil or other artificial flavorings and does not contain any real licorice root or glycyrrhizin.

Individuals with existing conditions like high blood pressure, heart disease, or kidney problems are more sensitive to the effects of glycyrrhizin and should avoid it. Pregnant women should also avoid licorice due to potential risks.

Yes, deglycyrrhizinated licorice (DGL) has had most of the glycyrrhizin removed and is generally considered safe for consumption, especially as a dietary supplement.

Products containing real licorice root will typically list licorice extract or glycyrrhizic acid in the ingredients. Always check the label to be certain.