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Read one chapter at a timeDGL (deglycyrrhizinated licorice) soothes the stomach lining and supports gut comfort.
Traditionally moistens a hot-dry sore throat and quiets a dry, tickly cough.
Harmonizer in compound formulas: softens harsh or bitter herbs (classical Persian and Chinese use).
Anti-inflammatory glabridin and licochalcone A flavonoids (a family of protective plant compounds).
Licorice root (Glycyrrhiza glabra: shirin-bayan / شیرینبیان) is one of the oldest and most widely used herbs in Persian, Chinese, Ayurvedic, and Western herbalism. Its intense sweetness — 30–50× sucrose — comes from glycyrrhizin, a triterpenoid saponin (soap-like plant compounds) that also drives licorice's more pronounced effects on cortisol clearance and blood pressure.
In classical Persian medicine (Ibn Sīnā, Aghili Khorasani), shirin-bayan is warm and moist, a mulattif (softener) that moistens dry-heat throats, quiets a hot-dry cough, and harmonises harsh herbs inside a compound formula. Modern practice separates two forms: whole licorice (short, targeted courses for throat and formula work) and DGL (deglycyrrhizinated licorice — the sweet flavonoids retained, glycyrrhizin removed, safe for daily gut-lining use without the blood-pressure caveats).
Short courses of whole root have shown functional-dyspepsia (indigestion) and post-operative sore-throat benefit in RCTs.
Persian temperament: Warm & Moist (1st degree). Ibn Sīnā (Al-Qānūn) and Aghili Khorasani (Makhzan al-Adwiya) place shirin-bayan as warm and moist in the first degree — a mulattif (softener) and munzij (ripener) for dry-hot throats and coughs, and a harmoniser (muṣliḥ) inside compound formulas. Its sweet moistness moderates the dryness and sharpness of bitter or hot herbs, ripens sticky phlegm so the chest can clear, and calms a scratchy voice.
In Persian, Chinese, and Western formulas alike, licorice (شیرینبیان) plays the same role — the harmoniser, added so the other herbs sit well together and act gently. It is read as sweet and moistening, which is why it's given for a dry raw throat, a hot dry cough, and a stomach lining that burns, and why it's avoided in damp, swollen conditions.
The classical caution is precise and matches modern practice: taken strong and daily over weeks it raises blood pressure and depletes potassium, so it belongs in small amounts, in short courses, and not at all in pregnancy.
It was used: sore throat, hoarseness, and dry cough. Gastric irritation, heartburn, and stomach-lining discomfort (DGL); eczema and skin inflammation (topical extract).
Its naturally sweet root has flavored teas, lozenges, syrups, and apothecary formulas from the Silk Road to Europe.
Primary compounds
Glycyrrhizin (glycyrrhizinic acid): triterpenoid saponin (soap-like plant compounds), 2–15% of dried root. The sweet principle and the mineralocorticoid-mimicking agent via 11β-HSD2 inhibition.
Glycyrrhetinic acid: glycyrrhizin's active aglycone metabolite. Anti-inflammatory and topically active in eczema.
Glabridin is prenylated isoflavan. Antioxidant, mild estrogenic in preclinical work, tyrosinase inhibitor (skin pigmentation).
Licochalcone A & B: retrochalcones. Anti-inflammatory and antimicrobial (slows the growth of germs) in vitro (in laboratory dishes, not in people).
Liquiritin & liquiritigenin: flavanones. Contribute to mucosal-soothing and antitussive activity.
Polysaccharides & mucilage (a soft, slippery plant gel) is moistening throat and gut-lining coat.
Strong evidence
Glycyrrhizin-driven pseudo-hyperaldosteronism (hypokalaemia, sodium retention, hypertension) is well-characterised. Effects begin around 100 mg glycyrrhizin/day and rise steeply above 400 mg/day.Strong evidence
Moderate evidence
Deglycyrrhizinated licorice (DGL) chewable (75 mg twice daily, 30 days) reduced dyspepsia (indigestion) symptom scores vs placebo in functional dyspepsia (double-blind RCT).Moderate evidence
Licorice gargle (0.5 g in 30 mL water, 1 min before induction) reduced post-operative sore throat and cough after endotracheal intubation vs placebo (RCT).Moderate evidence
Higher glycyrrhizin exposure from licorice intake in pregnancy was associated with shorter gestation and higher preterm-delivery odds in a Finnish birth cohort.Moderate evidence
Follow-up of the Finnish licorice cohort at age 13 found poorer cognitive (to do with thinking and memory), memory, and behavioural outcomes in high-exposure children.Moderate evidence
European Medicines Agency (HMPC) traditional-use monograph accepts Glycyrrhiza glabra L. radix for dyspepsia (indigestion) including heartburn, cough associated with cold, and inflammation of upper respiratory tract mucosa. Sets 100 mg glycyrrhizin/day upper limit for self-medication and 4–6 week maximum.Moderate evidence
Whole-root decoction (a drink made by simmering the plant in water): 1 tsp dried root simmered 10 min — small cup used for a sore throat or as a formula harmonizer. Short courses only (≤ 4–6 weeks).
Formula harmonizer: a small pinch added to bitter or drying herbal blends to smooth and sweeten.
Capsules and standardised extracts carry many times the amount you get from food, which is why the cautions below matter more here.
DGL chewable tablets (380–760 mg) chewed 15 minutes before meals for daily gut-lining support — safe long-term.
Digoxin — Whole licorice depletes potassium; hypokalaemia potentiates digoxin cardiotoxicity and arrhythmia risk. Concurrent use avoided; DGL acceptable. (high concern)
Thiazide & loop diuretics (furosemide, hydrochlorothiazide) — Additive potassium loss and sodium retention; risk of hypokalaemic arrhythmia and rising blood pressure on whole root. DGL acceptable. (high concern)
Corticosteroids (prednisolone, hydrocortisone) — Glycyrrhizin inhibits 11β-HSD2 and slows glucocorticoid metabolism; effectively raises steroid exposure and Cushingoid risk. Whole licorice avoided on chronic steroids; DGL acceptable. (high concern)
Antihypertensives (ACE inhibitors, ARBs, calcium blockers, beta-blockers) — Whole licorice opposes antihypertensive action via sodium retention and potassium loss; can push a well-controlled patient back into hypertension (high blood pressure). DGL acceptable. (high concern)
Warfarin — Case reports of altered INR (the blood test that shows how fast your blood clots) on whole licorice via CYP modulation and mild antiplatelet (medicines that stop blood cells sticking together, such as aspirin) direction; watch INR on any regular whole-root use. DGL acceptable. (moderate concern)
Oral contraceptives / hormone therapy — Glabridin shows mild estrogenic activity in preclinical work; concentrated extracts moderated in hormone-sensitive conditions. (low concern)
Antidiabetic medication — Glycyrrhizin-induced potassium loss can mildly worsen glucose control; additive with hypoglycaemics theoretical. Monitor on layered therapy. (low concern)
Avoid in kidney disease, heart failure, and low potassium.
Whole licorice can raise blood pressure and lower potassium — avoid daily long-term use, in pregnancy, and with high blood pressure.
Not to be combined with digoxin, thiazide/loop diuretics, or corticosteroids without a clinician (potassium loss compounds arrhythmia risk).
DGL is the daily-use form; save whole root for short-course throat and formula use.
Pregnancy — whole licorice associated with reduced gestational age and higher preterm-labour risk in observational (based on watching what people already do) data.
Hypertension (high blood pressure), heart failure, arrhythmia, and CKD — glycyrrhizin-driven potassium loss and sodium retention aren't safe backgrounds.
Hypokalaemia (already low potassium) from any cause.
Corticosteroid therapy — glycyrrhizin inhibits 11β-HSD2 and slows cortisol/prednisolone breakdown.
Pregnancy and breastfeeding
Whole licorice should be avoided in pregnancy. A long Finnish study (Räikkönen 2009, 2017) followed children whose mothers drank a lot of licorice tea or ate licorice sweets while pregnant. Those babies were born a little earlier, and by age thirteen they scored lower on some memory tests. A pinch of licorice as flavouring in food isn't the concern — the concern is a daily habit of strong tea, licorice candy, or standardised extract. DGL, the deglycyrrhizinated form, has not been studied in pregnancy either, so it's set aside for the same careful reason. While breastfeeding, an occasional lozenge for a sore throat is fine. A daily strong cup or standardised extract isn't, because it can raise the mother's blood pressure and lower her potassium.
Children
Small culinary licorice flavouring and short-course DGL under paediatric supervision are compatible from later childhood. Strong daily whole-root tea, confectionery amounts, and standardised extracts aren't appropriate in children — glycyrrhizin-driven hypokalaemia and hypertension (high blood pressure) have been reported in adolescents from heavy licorice-candy intake. Never give lozenges below choking age.
Older adults
Whole licorice deserves special care after sixty. Blood pressure tends to creep upward, potassium quietly runs lower, and many older adults are already on water pills, blood-pressure medicines, or heart-rhythm medicines — all of them poor partners for whole licorice. DGL, the deglycyrrhizinated form, is the everyday choice after sixty for a soothed stomach. A small warm cup of shirin-bayan for an occasional sore throat is fine — a short remedy, not a daily habit.
DGL vs regular licorice?
DGL has the glycyrrhizin removed, so it doesn't raise blood pressure or drop potassium. Use DGL for daily gut support. Reserve whole licorice for short courses — throat, formula harmonizer, adrenal-type fatigue after clinician review.
How long can I take whole licorice?
Most herbal traditions limit whole-root licorice to 4–6 weeks at a time, with breaks. Avoid it entirely with high blood pressure, heart disease, kidney disease, low potassium, or in pregnancy.
Why does licorice raise blood pressure?
Glycyrrhizin inhibits 11β-hydroxysteroid dehydrogenase type 2 — the enzyme that clears cortisol from mineralocorticoid receptors in the kidney. Cortisol builds up there, mimics aldosterone, and drives sodium retention and potassium loss. The effect is dose- and time-related; small culinary amounts are fine; daily strong tea isn't.
Is licorice tea safe every day?
Not the whole-root tea. DGL preparations are safe long-term. A strong daily whole-root decoction for months at a time can drive blood pressure up and potassium down, especially in adults over 60 or anyone on diuretics.
End of the Licorice guide