Sweet Medicine, Bitter Lesson: The Double Life of Licorice Root
You're in the pre-op bay, moments from anesthesia, when the nurse hands you a small lozenge that tastes faintly of licorice. It isn't for nerves—it's to calm the throat you'll wake up with. In trials, licorice gargles or lozenges given before intubation have cut postoperative sore throat roughly in half. [3]
TL;DR
Licorice root can be a gentle, timely coat for the throat before intubation and a 4–8 week course for stomach comfort, with promising evidence. But true licorice (with glycyrrhizin) can raise blood pressure and lower potassium, so dose carefully and know who should avoid it.
Practical Application
Who May Benefit:
Adults with functional dyspepsia seeking a trial of standardized extracts; surgical patients offered a pre‑intubation licorice gargle/lozenge to ease sore throat.
Who Should Be Cautious:
Uncontrolled hypertension; a history of arrhythmia; chronic kidney disease; those on potassium‑wasting diuretics or taking corticosteroids unless supervised.
Dosing: Digestive support in trials used 75 mg twice daily for 30 days or 150 mg once daily for 60 days of a standardized extract; topical gargle/lozenge is used immediately before intubation for sore throat prevention.
Timing: Think of licorice as either a **short, timely coat** for the throat (just before anesthesia) or a **4–8 week course** for stomach comfort.
Quality: Choose products that specify glycyrrhizin content. DGL (deglycyrrhizinated licorice) trims the compound most tied to blood‑pressure effects—useful if you’re cautious about BP.
Cautions: True licorice (with glycyrrhizin) can raise blood pressure and lower potassium; risks rise with high‑salt diets, heart/kidney disease, and with diuretics or corticosteroids. Stop and seek care for weakness, irregular heartbeat, or severe swelling.
The Great Harmonizer—and the Hidden Catch
For millennia, licorice has been the teammate herb—sweet, smoothing, blended into remedies from the Mediterranean to China. Ancient pharmacopeias placed it alongside treatments for cough, wounds, and digestive discomfort; today, it still shows up in teas, syrups, and supplements. [1] Yet "licorice" candy in the U.S. often contains no licorice at all, using anise oil for flavor—a detail that matters when we talk about safety and expectations. [1]
Modern regulators in Europe continue to evaluate licorice root as a herbal medicine for coughs and minor gut complaints—a nod to long-standing use as they update scientific assessments. [2]
When Research Stepped In: Stomach Stories
Consider the quiet misery of functional dyspepsia—the burn and bloat with no obvious lesion. In one double-blind trial, a standardized licorice extract (GutGard) taken for 30 days (75 mg twice daily) trimmed symptom scores by the second week and again by day 30 versus placebo. [4] In another randomized study, 150 mg daily over 60 days reduced Helicobacter pylori load on breath and stool antigen tests, hinting at antimicrobial help inside the stomach's storm. [5]
But licorice is no guaranteed ulcer cure. Older trials of deglycyrrhizinated licorice (DGL) for active gastric or duodenal ulcers failed to beat placebo for healing—sobering results that temper the folklore. [6]
A Throat, A Tube, A Simple Trick
Back to that lozenge: a meta-analysis of randomized trials finds that topical licorice—gargle or lozenge just before intubation—lessens the scratchy aftermath for many adults. Think of it as lining the throat's "velvet curtain" before the tube slides past. [3]
The Paradox: Sweet Root, High Pressure
Then there's the headline no one expects from an herb: a 54-year-old Massachusetts man died after weeks of daily black-licorice candy. "Even a small amount of licorice you eat can increase your blood pressure a little bit," cardiologist Neel Butala told reporters after describing the case for the New England Journal of Medicine. [11] The U.S. Food and Drug Administration has long warned that, for people over 40, about two ounces a day for two weeks can trigger an abnormal heart rhythm. As FDA physician Linda Katz puts it: "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." [8]
The culprit is glycyrrhizin, the natural sweet compound in true licorice. Inside the kidney, it blocks an enzyme that normally disarms cortisol before it can press the body's "salt-retaining" button. With the enzyme jammed, cortisol effectively impersonates aldosterone: sodium and water are hoarded, potassium is dumped, blood pressure climbs, and dangerous arrhythmias can follow. Doctors call this a look-alike syndrome—pseudo-hyperaldosteronism. [9] Case reports document emergencies from potent teas, candies, and even cough syrups. [10]
What Science Is Still Sorting Out
Licorice's chemistry is a crowded stage: beyond glycyrrhizin, flavonoids like licochalcones have anti-inflammatory and antimicrobial talents. That may explain the dyspepsia and H. pylori signals in modern trials—and why older, different extracts didn't match them. [4][5][6] Regulators are now revisiting monographs and reference lists to capture such nuances in new guidance. [2]
And then there's the curveball from virology's archives: during the 2003 SARS outbreak, researchers testing several compounds in infected cell cultures reported that "glycyrrhizin was the most active in inhibiting replication of the SARS-associated virus." It was a lab finding, not a clinical cure—but a reminder that this root still holds surprises. [7]
Making Licorice Work For You (Without Working Against You)
If you're exploring licorice for digestion, the trial-tested extracts give practical waypoints: 75 mg twice daily for 30 days, or 150 mg once daily for 60 days, depending on the product. [4][5] For sore throat after surgery, it's about timing—a lozenge or gargle just before the tube goes in. [3] To lower risk, look for deglycyrrhizinated (DGL) products when you don't need glycyrrhizin's effects; DGL trims the very compound that can raise blood pressure. [1][8]
Two more safety checkpoints matter in real life:
- Labels: many "licorice" candies are actually anise-flavored and contain no licorice—don't assume benefits or risks without checking. [1]
- Med lists: licorice can interact with drugs that shift fluids or electrolytes (e.g., diuretics) and with corticosteroids; if you have high blood pressure, heart, or kidney disease, involve your clinician. [1]
The Takeaway
Licorice root can be a gracious host—easing dyspepsia in select trials and sparing throats after surgery—yet it can also quietly rearrange your body's salt-and-potassium housekeeping. The difference lies in the extract, the dose, the duration, and you. Respect those variables, and the old "harmonizer" has a better chance of singing on key. [3][4][5][8][9]
Key Takeaways
- •Licorice's modern use mirrors its history: soothing cough, throat, and minor digestive complaints, yet U.S. "licorice" candies often use anise oil, not licorice.
- •Topical licorice before intubation reduces the incidence and severity of postoperative sore throat; it's a short, timed intervention just before anesthesia.
- •Standardized extract for dyspepsia showed benefits by days 15–30; trials used 75 mg twice daily for 30 days or 150 mg once daily for 60 days (GutGard).
- •Think in two modes: quick throat coat pre-procedure, or a defined 4–8 week stomach course—then reassess.
- •Safety is the hidden catch: glycyrrhizin can raise blood pressure and lower potassium, with higher risk in high-salt diets, heart/kidney disease, or with diuretics/corticosteroids.
- •Stop and seek care if you develop weakness, irregular heartbeat, or severe swelling.
Case Studies
Hypertensive emergency after daily licorice tea; older adult with severe blood pressure elevation and electrolyte changes.
Source: CMAJ 2019 case report [10]
Outcome:Stopping licorice and correcting potassium resolved the crisis.
Massachusetts man consuming a bag and a half of black licorice daily died from arrhythmia linked to low potassium.
Source: NEJM case reported in news coverage (WBUR/AP) 2020 [11]
Outcome:Fatal arrhythmia; prompted renewed public warnings.
Life-threatening pseudo-aldosteronism from excessive licorice intake.
Source: BMC Endocrine Disorders 2021 case report [9]
Outcome:Recovery after stopping licorice and correcting electrolytes.
Expert Insights
""Even a small amount of licorice you eat can increase your blood pressure a little bit."" [11]
— Neel Butala, MD, cardiologist, Massachusetts General Hospital Comment on NEJM licorice case (2020)
""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."" [8]
— Linda Katz, MD, U.S. FDA FDA Consumer Update on black licorice safety
""Glycyrrhizin was the most active in inhibiting replication of the SARS-associated virus."" [7]
— Cinatl et al., The Lancet (2003) In‑vitro antiviral testing during the SARS outbreak
Key Research
- •
Standardized licorice extract (GutGard) reduced functional dyspepsia symptoms by day 15 and day 30 vs. placebo. [4]
A 30-day, double-blind RCT using 75 mg twice daily.
Suggests certain extracts may ease upper-GI discomfort within weeks.
- •
Topical licorice before intubation reduces postoperative sore throat incidence and severity. [3]
Systematic review/meta-analysis of randomized trials.
Simple timing—not long courses—drives this benefit.
- •
Daily 150 mg of GutGard for 60 days lowered H. pylori gastric load vs. placebo. [5]
Randomized, double-blind trial using breath and stool antigen tests.
Points to antimicrobial activity in vivo; not a stand-alone eradication regimen.
- •
Older RCTs of DGL for active ulcers showed no advantage over placebo. [6]
Cross-over and parallel trials from the 1960s–70s.
Balances enthusiasm with negative evidence.
- •
Glycyrrhizin blocked SARS-CoV replication in cell cultures. [7]
Rapid in-vitro screen during the 2003 SARS outbreak.
Mechanistic intrigue, not clinical guidance.
Licorice’s lesson is old and modern at once: a plant can be a gentle negotiator—softening an injury or a symptom—while also tipping a hidden lever that changes the body’s chemistry. Wisdom lies in knowing which part of the plant you’re inviting in, and for how long.
Common Questions
Does black licorice candy provide the same benefits as licorice root?
Often no—many U.S. "licorice" candies use anise oil for flavor and contain no licorice, so benefits and risks won't match true licorice.
What dosing did studies use for digestive support?
Standardized extract trials used 75 mg twice daily for 30 days or 150 mg once daily for 60 days (GutGard).
How is licorice used to prevent postoperative sore throat?
As a topical gargle or lozenge given shortly before anesthesia and intubation to reduce sore throat incidence and severity.
Who should avoid or be cautious with licorice?
People with high-salt diets, heart or kidney disease, or those taking diuretics or corticosteroids should be cautious due to blood pressure and potassium effects.
Can licorice raise blood pressure or affect heart rhythm?
Yes—true licorice with glycyrrhizin can raise blood pressure and lower potassium; excessive intake has been linked to irregular heart rhythms.
How long should I take licorice for digestive comfort?
Use a defined course of about 4–8 weeks as studied, then reassess whether to continue or stop.
Sources
- 1.
- 2.
- 3.Topical application of licorice for prevention of postoperative sore throat in adults: systematic review and meta‑analysis (2019) [link]
- 4.An Extract of Glycyrrhiza glabra (GutGard) Alleviates Symptoms of Functional Dyspepsia: Randomized, Double‑Blind, Placebo‑Controlled Study (2011) [link]
- 5.Effect of GutGard in the Management of Helicobacter pylori: A Randomized Double‑Blind Placebo‑Controlled Study (2013) [link]
- 6.Double‑blind trial(s) of deglycyrrhizinated licorice in gastric/duodenal ulcer (no benefit vs placebo) (1973) [link]
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