The Halloween candy the FDA warns adults over 40 about isn’t chocolate — and 2 ounces a day for two weeks could throw off your heart rhythm

by Adrienne Erin

The candy bowl comes out in October, and it tends to stay out well into November. Most people over 40 know to go easy on the chocolate and the sugar. But the treat that has actually earned a specific warning from the U.S. Food and Drug Administration is one many people think of as old-fashioned and harmless: black licorice.

Key Takeaways

  • The FDA warns that if you’re 40 or older, eating 2 ounces of black licorice a day for at least two weeks could land you in the hospital with an irregular heart rhythm (arrhythmia).
  • The culprit is glycyrrhizin, a natural sweetener in licorice root that can make potassium levels drop and blood pressure rise.
  • Black licorice can interact with some medications, including certain diuretics (water pills), heart medications such as digoxin, and blood pressure drugs. It may also make warfarin less effective.
  • Most red licorice, and many U.S. “licorice-flavored” candies, contain little or no licorice root, so the warning doesn’t apply to them.
  • An occasional piece is fine for most people. People with high blood pressure, heart disease or kidney disease should be especially cautious.

What the FDA actually warns

The FDA’s advice is specific: if you’re 40 or older, eating 2 ounces of black licorice a day for at least two weeks could cause an irregular heart rhythm serious enough to need hospital care. Two ounces is about 57 grams, an amount that’s easy to reach day after day if a bag sits on your desk or kitchen counter.

The agency also advises everyone, at any age, not to eat large amounts of black licorice at one time. If you’ve been eating a lot of it and notice an irregular heartbeat or muscle weakness, the FDA says to stop eating it immediately and contact your health care provider. According to the FDA, potassium levels usually return to normal with no lasting health problems once people stop eating it.

How a candy can affect your heart

Real black licorice gets its flavor from the root of the licorice plant, which contains a compound called glycyrrhizin. Glycyrrhizin is about 50 times sweeter than table sugar.

In larger amounts, glycyrrhizin causes the kidneys to hold on to sodium and water while flushing out potassium. The result can be high blood pressure, swelling from fluid retention, and low potassium levels. Potassium helps regulate the heartbeat, so when it falls too low, the heart’s rhythm can become irregular, and in rare cases dangerously so. Other possible effects include muscle weakness, fatigue and, in people with weakened hearts, congestive heart failure.

The risk isn’t only theoretical. In 2020, doctors reported in The New England Journal of Medicine the case of a 54-year-old Massachusetts man who died of cardiac arrest after eating about a bag and a half of black licorice every day for several weeks. He had switched from red licorice to black licorice only a few weeks earlier. That case involved an extreme amount, but it illustrates how serious the effect can become.

Even smaller amounts may matter. A randomized trial published in 2024 in The American Journal of Clinical Nutrition found that a low daily dose of licorice affected hormones that regulate blood pressure and raised home blood pressure readings.

The medication problem

The FDA notes that black licorice can interact with some medications, herbs and dietary supplements. The interactions that matter most include:

  • Diuretics (water pills) that lower potassium. Combined with licorice, they could cause dangerously low potassium.
  • Digoxin, a heart medication. Low potassium raises the risk of digoxin side effects, including heart rhythm problems.
  • Blood pressure medications. Because licorice causes salt and water retention, it may make them less effective.
  • Corticosteroids, which can also lower potassium.
  • Warfarin. Licorice may make this blood thinner less effective, which raises the risk of clots.

If you take any of these, ask your doctor or pharmacist before eating black licorice regularly or taking licorice supplements.

Where else glycyrrhizin hides

Licorice candy isn’t the only source. Licorice root is also sold as a dietary supplement, in capsules, tablets and liquid extracts, and it’s an ingredient in some herbal teas. According to the National Institutes of Health, even small amounts of glycyrrhizin from licorice root products have been linked to severe side effects in people who eat a lot of salt, have high blood pressure, or have heart or kidney conditions.

On the other hand, many licorice-flavored products made in the U.S. use anise oil, which tastes and smells similar but contains no glycyrrhizin. Red licorice contains little or no licorice root. And supplements labeled “DGL” (deglycyrrhizinated licorice) have had the glycyrrhizin removed.

What to do with this information

Enjoy it in moderation. An occasional piece of black licorice is fine for most healthy people. The concern is daily eating over weeks.

Check the label. Look for “licorice extract,” “licorice root” or “glycyrrhizin” on candy, teas and supplements.

Be extra careful if you have certain conditions. People with high blood pressure, heart disease or kidney disease should avoid black licorice or ask their doctor first.

Review your medications. If you take a diuretic, digoxin, blood pressure medication, corticosteroid or warfarin, talk to your pharmacist about licorice.

Know the warning signs. Stop eating it and call your doctor if you notice an irregular or racing heartbeat, muscle weakness, swelling or unusual fatigue.

This article is for general information and isn’t a substitute for advice from your doctor or pharmacist.

Sources:

Adrienne Erin

Adrienne holds a Bachelor of Science in Kinesiology, where she developed a strong foundation in exercise physiology and human nutrition. Before joining DailyHealthPost, she spent several years writing about health and wellness topics, translating nutrition and fitness research into practical guidance for everyday readers.

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