Does Eating Too Much Licorice Cause Diarrhea?

Diarrhea can occur from eating too much licorice, but it is one of the rarer gastrointestinal symptoms rather than the hallmark effect. A comprehensive review of licorice toxicity published in 2023 found that GI symptoms including diarrhea, abdominal pain, nausea, and vomiting are uncommon compared to the condition’s better-known consequences: dangerously low potassium, high blood pressure, and fluid retention.¹ The bigger concern with excessive licorice consumption is not what it does to your gut but what it does to your heart and kidneys, which makes the diarrhea question worth exploring in full context.

Why Licorice Affects the Body So Broadly

The active compound behind most of licorice’s effects is glycyrrhizic acid (sometimes called glycyrrhizin), found naturally in the root of the licorice plant. When you eat real licorice, glycyrrhizic acid interferes with an enzyme that normally keeps the stress hormone cortisol from activating your kidney’s sodium-retention pathways. With that enzyme blocked, cortisol floods those pathways and your body starts acting as though it has too much of a hormone called aldosterone, even though aldosterone levels are actually suppressed. Researchers call this pseudohyperaldosteronism.

In a study of six healthy men given roughly 500 mg of glycyrrhizic acid per day for just seven days, the signs were already measurable: body weight went up from fluid retention, potassium levels dropped, and the hormonal markers of this false aldosterone state appeared within three days.² The speed of onset is striking. Seven grams of a commercial licorice preparation daily was enough. That is not an enormous amount if you are someone who snacks on black licorice regularly or takes licorice-containing herbal supplements.

This hormonal disruption is what drives most of licorice’s systemic effects. Low potassium affects muscle contractions everywhere in the body, including in the walls of the intestines. High sodium causes water retention, which can alter how fluid moves through the gut. The diarrhea question sits downstream of this broader metabolic disturbance.

How Diarrhea Fits Into the Picture

When licorice toxicity reports describe GI symptoms, diarrhea shows up on the list but rarely as the chief complaint. The 2023 narrative review that cataloged clinical manifestations of licorice toxicity across the published literature characterized GI symptoms as rare overall.¹ Patients who present to emergency departments after overdoing licorice typically arrive with muscle weakness, heart rhythm disturbances, or dangerously elevated blood pressure. The digestive complaints, when they occur, tend to be secondary observations noted during workup.

That said, there are plausible reasons why eating a lot of licorice could loosen your stools even before you reach toxicity levels. Licorice root has been used in traditional Chinese medicine for centuries specifically to regulate gastrointestinal function.³ Some of its compounds influence how quickly the gut contracts and moves contents along. At moderate doses, this might relieve constipation. At higher doses or in sensitive individuals, the same mechanism could push things too far in the other direction.

Another factor is bile. In animal studies, licorice extract produced a significant choleretic effect, meaning it increased the rate at which bile was excreted into the intestine.⁴ Excess bile in the colon is a well-known trigger for loose, watery stools. If you have ever experienced diarrhea after a particularly fatty meal, a similar mechanism may be at play. With licorice, the bile flow increase happens through a different pathway but produces comparable downstream effects in the gut.

Licorice’s Paradoxical Laxative Reputation

Here is where the story gets genuinely interesting. While diarrhea as a toxic side effect of licorice is uncommon, licorice has a long history of being used intentionally as a mild laxative. Ancient Chinese medical texts documented the laxative properties of raw licorice, and modern research has begun to explore why.⁵ A 2025 study found that licorice water extract improved constipation in animal models by repairing the intestinal barrier and shifting the composition of gut bacteria.

This dual nature, where the same plant can be described as both a GI remedy and a potential cause of GI distress, makes more sense when you think about dose. At the amounts used in traditional medicine, licorice gently promotes motility and may help normalize stool consistency. Herbal formulations designed for constipation-predominant irritable bowel syndrome have included licorice root as one of several ingredients aimed at increasing stool frequency.⁶ In one such formulation, licorice was combined with slippery elm bark, lactulose, and oat bran specifically to normalize bowel habits in people with constipation-type IBS.

Similarly, a study on a three-herb mixture containing licorice (Glycyrrhiza uralensis) found laxative effects in constipated rats, measured by increases in stool frequency, stool weight, and intestinal mucin secretion.⁷ The evidence collectively suggests that licorice has genuine effects on gut motility and stool consistency. Eating a large amount of real licorice is, in a sense, giving yourself an uncontrolled dose of a mild herbal laxative on top of whatever systemic effects the glycyrrhizic acid is producing. Diarrhea in that context is not mysterious at all.

What Your Gut Bacteria Do with Glycyrrhizin

Your intestinal bacteria play an active role in processing licorice compounds, and individual differences in gut flora may help explain why some people get digestive symptoms from licorice and others do not. When glycyrrhizin reaches the lower gut, resident bacteria break it down into glycyrrhetinic acid, the compound that is actually responsible for most of the hormonal effects. Specific bacterial species drive this conversion: research identified Eubacterium and Streptococcus strains as the key players in metabolizing glycyrrhizin into its active form.⁸

This means the effective dose of active licorice compounds you absorb depends partly on which bacteria happen to live in your gut. Someone with an abundance of the bacteria that rapidly convert glycyrrhizin might experience stronger effects, both systemic and digestive, from the same amount of licorice. It also means that the fermentation process itself, which generates gas and other metabolic byproducts in the colon, could contribute to bloating or loose stools independently of the hormonal mechanism. If you have noticed that licorice bothers your stomach while a friend eats it freely, differences in your respective microbiomes are a reasonable explanation.

The Risks That Should Worry You More Than Diarrhea

If you are reading this because you ate a lot of licorice and got diarrhea, the good news is that the digestive disturbance itself is unlikely to be dangerous. The bad news is that the same amount of licorice that bothered your gut may be doing more consequential things elsewhere. The potassium depletion caused by glycyrrhizic acid is the real clinical concern with excessive licorice intake, and it can become severe enough to be life-threatening.

In one reported case, a 74-year-old woman who consumed large quantities of black licorice presented with potassium levels of 2.4 mmol/L, well below the normal range. She was already taking fludrocortisone for low blood pressure, which compounded the problem.⁹ In a more extreme case, a 62-year-old woman who had consumed licorice-containing health supplements daily for five months went into cardiac arrest from ventricular fibrillation caused by profound hypokalemia, with potassium levels of just 1.6 mEq/L.¹⁰ That case was fatal despite intensive care.

These are extreme examples, and most people who eat licorice candy occasionally will never approach those levels of exposure. But they illustrate why the medical literature on licorice toxicity focuses so heavily on potassium, blood pressure, and cardiac rhythm rather than on diarrhea. The GI symptoms, when they appear, are a minor subplot in a more serious metabolic story.

How Much Licorice Is Actually Too Much

Pinning down a safe threshold is tricky because glycyrrhizic acid content varies enormously across products. A piece of black licorice candy might contain anywhere from a trace amount to a surprisingly high dose, depending on the brand and whether it uses real licorice extract or synthetic flavoring. Many “licorice” candies sold in the United States are flavored with anise oil rather than actual licorice root, which means they contain no glycyrrhizic acid at all and pose none of these risks.

For products that do contain real licorice, the study cited earlier showed measurable hormonal changes from 500 mg per day of glycyrrhizic acid within a week.² Some regulatory bodies in Europe have suggested that regular intake above 100 mg per day of glycyrrhizic acid warrants caution, though specific thresholds vary by country. The FDA has warned that eating two ounces of black licorice per day for at least two weeks could cause heart rhythm problems in people over 40, though it has not set a formal regulatory limit on glycyrrhizic acid content in food.

For the diarrhea question specifically, the threshold is almost certainly lower than the threshold for serious toxicity. The laxative and bile-stimulating effects of licorice can kick in at amounts that are nowhere near dangerous from a potassium standpoint. If you are someone who eats real black licorice regularly and notices looser stools, you are probably experiencing the mild laxative action of the root extract long before you are in any metabolic danger.

Real Licorice vs. Licorice-Flavored Candy

This distinction matters a lot and trips people up constantly. The flavor most Westerners associate with licorice, that distinctive sweet-sharp-anise taste, comes from anethole, a compound found in both licorice root and anise. Many commercial licorice candies, particularly in North America, use anise oil for flavoring and contain no actual licorice root extract. These products will not cause any of the effects discussed in this article, whether diarrhea or potassium depletion, because they lack glycyrrhizic acid entirely.

Products that do contain real licorice typically say so on the label, sometimes listed as “licorice extract,” “licorice root,” or “glycyrrhiza glabra.” European licorice candies, Dutch drop, Scandinavian salty licorice, and certain herbal teas and supplements are more likely to contain the real thing. If you are trying to figure out whether your licorice habit could be causing GI issues, check the ingredient list. If it lists only anise or “natural and artificial flavors” without mentioning licorice root, the candy is not the culprit.

Herbal supplements present a separate concern. Licorice root is a common ingredient in traditional herbal formulations, sometimes in concentrated forms that deliver far more glycyrrhizic acid per dose than you would get from candy. The fatal cardiac case mentioned earlier involved licorice-containing health supplements taken daily for months.¹⁰ Deglycyrrhizinated licorice (DGL) supplements have had the glycyrrhizic acid removed and are marketed specifically for people who want the digestive benefits of licorice without the hormonal risks. DGL is widely available and is a reasonable option for anyone who finds licorice soothing for the stomach but wants to avoid the potassium and blood pressure effects.

Who Is Most Vulnerable

Certain groups face outsized risk from licorice overconsumption, and the GI effects can serve as an early warning worth paying attention to. Older adults are more susceptible to the potassium-depleting effects because kidney function tends to decline with age, making it harder to compensate for the mineral imbalance. Both reported severe cases described earlier involved women in their sixties and seventies.

People taking certain medications face compounded risk. Diuretics, particularly the thiazide and loop types commonly prescribed for blood pressure, already lower potassium. Adding licorice on top accelerates potassium loss. Corticosteroids and fludrocortisone, as in the case of the 74-year-old patient, work through similar hormonal pathways and create an additive effect.⁹ Anyone on blood pressure medication, heart medication, or hormonal therapy should be especially cautious about regular licorice consumption.

People with existing heart conditions, kidney disease, or electrolyte disorders are also at heightened risk. Pregnant women are typically advised to avoid large amounts of licorice, as some research has raised concerns about effects on fetal development, though that evidence comes from a separate line of study than the toxicity literature discussed here. The bottom line for vulnerable groups is that if licorice is giving you diarrhea, your body may be telling you something worth listening to before more serious effects develop.

When Diarrhea from Licorice Warrants a Doctor Visit

Occasional loose stools after eating a bag of licorice candy are not a medical emergency. Your gut responded to a mild laxative stimulus, and things will normalize once the licorice clears your system. But a few scenarios deserve more attention. If you have been consuming real licorice products regularly for weeks and are experiencing diarrhea alongside muscle weakness, cramping, or heart palpitations, those are signs of potassium depletion, and you should get your electrolytes checked. The combination of GI disturbance with muscle or cardiac symptoms is the red flag.

Similarly, if you are taking licorice-containing herbal supplements and develop persistent digestive changes, do not assume the supplement is harmless because it is “natural.” Concentrated licorice root extract can deliver glycyrrhizic acid doses that dwarf what you would get from candy. And if you have any of the risk factors mentioned above, particularly if you take diuretics or have heart disease, even moderate regular licorice intake is worth mentioning to your doctor, who can monitor potassium levels with a simple blood test.