Licorice and Medications: Unexpected Interactions with a Common Candy

Most people think of licorice as just a sweet, chewy candy-something you grab at the checkout counter or share with kids during movie night. But if you’re taking any kind of medication, that little black stick could be doing more than satisfying a sweet tooth. It might be messing with your blood pressure, draining your potassium, or even making your pills less effective-or dangerously strong.

What’s Really in Licorice?

Not all licorice is the same. The kind that can cause serious health issues contains glycyrrhizin, a compound pulled from the root of the licorice plant. This isn’t just flavoring-it’s a powerful substance that acts like a hormone in your body. Glycyrrhizin blocks an enzyme that normally keeps cortisol (your stress hormone) from overstimulating your kidneys. The result? Your body starts holding onto salt and water while flushing out potassium. That’s how you end up with high blood pressure and low potassium, even if you’ve never had either problem before.

Here’s the catch: most candy labeled "licorice" in the U.S. doesn’t contain any real licorice at all. Instead, it’s flavored with anise oil, which tastes similar but doesn’t carry the same risks. Real licorice candy-usually darker, stickier, and imported from Europe-is the one you need to watch out for. And it’s not just candy. Herbal supplements, teas, and extracts often pack way more glycyrrhizin than you’d expect. Some contain up to 24% glycyrrhizin by weight. That’s like swallowing a teaspoon of pure medicine every day.

How Licorice Interacts With Common Medications

If you’re on any of these medications, eating licorice regularly could be dangerous:

• Diuretics (water pills) like hydrochlorothiazide or furosemide: These already make you lose potassium. Licorice does the same thing. Together, they can crash your potassium levels below 3.0 mmol/L-enough to trigger muscle cramps, irregular heartbeat, or even sudden cardiac events.
• High blood pressure meds like lisinopril, losartan, or amlodipine: Licorice fights against them. It causes fluid retention and raises blood pressure, undoing the work of your medication. One patient reported his BP jumping from 120/80 to 165/95 after just three days of eating 30 grams of licorice daily.
• Heart meds like digoxin: Low potassium makes digoxin way more toxic. There are documented cases of people needing hospitalization after eating licorice while on digoxin, even when they’d been stable for years.
• Warfarin and other blood thinners: Some studies suggest licorice can either increase or decrease the effect of these drugs. One patient’s INR (a measure of blood clotting) dropped sharply after eating licorice while on phenprocoumon. Another saw dangerous bleeding after combining licorice with warfarin. The mechanism isn’t fully understood, but the risk is real.
• Corticosteroids like fludrocortisone: This one’s especially tricky. Fludrocortisone already mimics aldosterone (a hormone that retains salt and loses potassium). Add licorice, and you’re doubling down on the same effect. One patient developed blood pressure of 205/110 and a panic attack after eating licorice while on this drug-despite no prior issues.

Even if you’re not on meds, long-term use can cause problems. The European Food Safety Authority says 100 mg of glycyrrhizin per day is the safe limit for healthy adults. That’s about 50 grams of traditional black licorice candy. Eat more than that for two weeks straight, and you’re playing with fire.

The Hidden Danger: You Don’t Know What You’re Eating

A 2023 Consumer Reports survey found that 78% of black licorice products didn’t list glycyrrhizin content on the label. Nine out of ten didn’t warn about drug interactions. Most people assume if it says "licorice flavor," it’s safe. It’s not. And even when it does say "real licorice," you still won’t know how much glycyrrhizin is in it.

Supplements are even worse. A typical licorice root capsule might contain 400 mg of extract-but without knowing the glycyrrhizin percentage, you could be ingesting 50 mg or 200 mg. That’s the difference between a harmless snack and a medical emergency.

And then there’s deglycyrrhizinated licorice (DGL). This version has the glycyrrhizin removed, so it’s safe for people on meds. It’s often used for heartburn or stomach ulcers. But unless the label says "DGL," assume it’s the risky kind.

Who’s at Risk-and What to Do

You don’t have to be a licorice addict to be in danger. One case study described a 47-year-old man who ate 200 grams of licorice daily (about 200-400 mg glycyrrhizin) for three weeks. He ended up with a blood pressure of 210/120 and potassium levels of 2.6 mmol/L-far below the normal range of 3.5-5.0. He needed hospitalization.

Older adults, people with existing high blood pressure or heart disease, and those taking multiple medications are at highest risk. But even young, healthy people can develop symptoms if they eat a lot over time.

If you’ve been eating licorice regularly and you’re on any medication, here’s what to do:

1. Stop eating it immediately.
2. Check your blood pressure and watch for swelling, headaches, muscle weakness, or heart palpitations.
3. Call your doctor or pharmacist. Tell them exactly how much and how often you’ve been eating it.
4. Ask for a blood test to check your potassium and sodium levels.

Don’t wait for symptoms. If you’re on blood pressure meds or diuretics, it’s better to be safe than sorry.

What About Licorice Supplements?

Supplements are where things get really murky. Many are marketed for "digestive health," "adrenal support," or "natural energy." But unless they’re labeled DGL, they’re likely loaded with glycyrrhizin. And unlike prescription drugs, supplements aren’t required to prove safety or list exact ingredient amounts.

Even worse, some herbal blends combine licorice with other plants like Euphorbia kansui. Studies show these combinations can be effective-but only if licorice makes up less than half the mix. If it’s more than 50%, toxicity spikes dramatically. No label will tell you that.

Bottom line: if you’re taking any medication, avoid licorice supplements unless your doctor says it’s safe-and even then, get a clear dosage of glycyrrhizin.

What’s Being Done?

Regulators are starting to catch up. The UK requires warning labels on products with more than 100 mg of glycyrrhizin per serving. Japan limits licorice supplements to 100 mg per day. The FDA has flagged licorice as a "high-priority" interaction risk in its 2023 draft guidance. And by 2026, the American Herbal Pharmacopoeia wants all licorice products to list glycyrrhizin content on the label.

But right now, the burden is on you. Pharmacists in one 2021 study could correctly identify only 37% of major licorice-drug interactions. That means you’re probably the only one paying attention to your candy and your pills.

Final Advice

If you’re not on any medication and you eat licorice occasionally-say, a few pieces once a month-you’re probably fine. But if you’re on blood pressure meds, diuretics, heart meds, or anything that affects your electrolytes, skip it. Seriously. Even if you think you’re being careful, you can’t tell how much glycyrrhizin is in that bag.

And if you love the taste? Try anise-flavored candy instead. Or look for DGL products if you need licorice for digestive reasons. But always read the label. If it doesn’t say "deglycyrrhizinated," assume it’s the dangerous kind.

Your body doesn’t distinguish between candy and medicine. If it contains glycyrrhizin, it’s acting like a drug. And drugs don’t play nice with other drugs.