Licorice and Medications: Unexpected Interactions with a Common Candy

Most people think of licorice as a sweet, chewy candy-something you grab for a treat or maybe to freshen your breath. But if you’re taking any kind of medication, that piece of black licorice might be doing more than just satisfying a craving. It could be quietly messing with your blood pressure, draining your potassium, or even canceling out the effects of your prescription drugs. And you probably have no idea.

What’s Really in Licorice?

Not all licorice is the same. The real stuff comes from the root of the Glycyrrhiza glabra plant. What makes it dangerous for some people isn’t the sugar-it’s a compound called glycyrrhizin. This chemical mimics aldosterone, a hormone your body uses to control salt and water balance. When glycyrrhizin sticks around too long, your body starts holding onto sodium and flushing out potassium. That sounds harmless until you realize what that does to your heart and muscles.

Traditional black licorice candy usually contains 0.5% to 2% glycyrrhizin. That means eating just 50 grams a day-about two small bags-could push you past the safe daily limit of 100 mg set by the European Food Safety Authority. Some herbal supplements? They can pack in 4% to 24%. And guess what? Most candy labels don’t tell you how much glycyrrhizin is in there. You’re flying blind.

And here’s the twist: a lot of products labeled “licorice” aren’t licorice at all. Anise oil gives that same sweet, earthy flavor without any glycyrrhizin. So if you’re eating red licorice or those chewy twists from the candy aisle, you’re probably fine. But if you bought a bag labeled “traditional black licorice” or picked up a herbal tea labeled “licorice root,” you’re risking a real interaction.

How Licorice Breaks Your Medications

The problem isn’t just one thing-it’s a chain reaction. Glycyrrhizin doesn’t just mess with your electrolytes. It interferes with how your body processes drugs. Some medications become stronger. Others vanish before they can work.

Take blood pressure meds. If you’re on lisinopril, losartan, or any ACE inhibitor or ARB, licorice can undo their benefits. One Reddit user reported his blood pressure jumped from 120/80 to 165/95 after eating 30 grams of licorice daily for just three days. That’s not an outlier. A 2019 report from New Zealand’s Medsafe described a man on fludrocortisone-already a salt-retaining drug-who developed panic attacks and blood pressure of 205/110 after eating licorice. He had no history of hypertension. The licorice pushed him over the edge.

Diuretics like hydrochlorothiazide or furosemide? They make you lose potassium. Licorice does the same. Together? You’re at risk of dropping below 3.0 mmol/L, which can trigger muscle cramps, irregular heartbeat, or even cardiac arrest. The University of Rochester Medical Center has documented cases where patients on thiazide diuretics developed dangerous hypokalemia after adding licorice to their routine.

And then there’s warfarin. Some studies say licorice makes warfarin stronger-raising your INR and risk of bleeding. Others say it weakens it. A 2021 case report described a 92-year-old woman whose INR suddenly dropped after eating licorice while taking phenprocoumon, another blood thinner. Her doctors couldn’t figure out why until they asked about her candy habit. That’s the problem: the effect isn’t consistent. It depends on your genes, your liver, and what kind of licorice you’re eating.

Even metformin, the common diabetes drug, might be affected. Animal studies show licorice juice reduces metformin’s effectiveness. No human trials confirm it yet-but why risk it if you’re trying to control your blood sugar?

Who’s at the Highest Risk?

You don’t need to be sick to be in danger. But certain people are sitting on a ticking clock.

• Anyone over 40-your body handles electrolytes less efficiently with age.
• People with high blood pressure, heart disease, or kidney problems-your systems are already under strain.
• Those on corticosteroids like prednisone or fludrocortisone-licorice amplifies their salt-retaining effects.
• People taking digoxin-low potassium from licorice can trigger deadly heart rhythm problems. A 2002 case report showed a patient with digoxin toxicity after eating licorice daily for weeks.
• Anyone taking CYP3A4 or CYP2D6 substrates-like cyclosporine, statins, or certain antidepressants. Licorice can both induce and inhibit these enzymes, depending on the product. It’s unpredictable.

And here’s the kicker: you don’t need to eat a lot. Two weeks of 100 mg glycyrrhizin per day is enough to start seeing problems. That’s less than a bag of candy per week. Most people don’t realize they’re even consuming it.

What About DGL Licorice?

If you’re taking licorice for stomach issues-like acid reflux or ulcers-you might have heard of DGL. That stands for deglycyrrhizinated licorice. It’s been stripped of glycyrrhizin, so it doesn’t raise blood pressure or lower potassium. It’s safe for most people on meds.

But here’s the trap: DGL isn’t labeled clearly. If you buy “licorice root capsules” or “licorice extract,” you have no idea what’s in them. Always check the label for “deglycyrrhizinated” or “glycyrrhizin-free.” If it’s not stated, assume it’s the real stuff-and dangerous if you’re on medication.

What Should You Do?

If you’re on any medication and you eat licorice, here’s what to do right now:

1. Stop eating black licorice candy or herbal supplements with licorice root until you talk to your doctor.
2. Check your medicine cabinet. Look at every supplement. If it says “licorice root,” “Glycyrrhiza glabra,” or “licorice extract,” put it aside.
3. Ask your pharmacist: “Does my medication interact with licorice?” Don’t assume they know. A 2021 study found only 37% of community pharmacists could list all major licorice-drug interactions.
4. If you’ve been eating licorice regularly and feel weak, bloated, have headaches, or notice your heart racing, get your potassium and blood pressure checked immediately.
5. If you’re on blood thinners, ask your doctor to check your INR within a week of stopping or starting licorice.

There’s no need to panic. But you do need to be aware. Licorice isn’t the villain-it’s the quiet one. It doesn’t scream. It doesn’t come with a warning label. It just sits there in the candy aisle, next to the gummy bears, waiting for someone to eat it without knowing what it’s doing inside their body.

The Bigger Picture

This isn’t just about candy. It’s about how we treat natural products. We assume “natural” means “safe.” But licorice is a plant with powerful chemistry. It’s used in traditional medicine for a reason-because it works. And that’s exactly why it can hurt you.

The global licorice market is worth over $1.3 billion. Supplements make up a third of it. And nearly 78% of black licorice products don’t list glycyrrhizin content. The FDA doesn’t require it. The UK now demands warning labels on products with over 100 mg per serving, but most countries don’t. You’re on your own.

Future rules might change. The American Herbal Pharmacopoeia wants mandatory glycyrrhizin labeling by 2026. The European Commission is considering reclassifying high-glycyrrhizin licorice as a medicine, not food. But for now? It’s your responsibility to know what you’re eating.

Next time you reach for that black licorice stick, ask yourself: Is this worth the risk? Because your meds might be working fine-until they suddenly aren’t.