Liquorice tea

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About this tea
Origin and tradition
TCM properties
Traditional uses
Ingredients
Method
Variations and pairings
When to drink it
Cautions and contraindications
Frequently asked questions
Related pages

1. About this tea

Liquorice tea — gan cao cha (甘草茶) — is an infusion of the dried root of Glycyrrhiza uralensis, the Chinese liquorice. The name means simply "sweet grass", and the tea lives up to it: pale straw-gold, thick-tasting and startlingly sweet, some fifty times sweeter than sugar by weight, with the distinctive aniseed-adjacent flavour that people either love or cannot abide.

Liquorice is the most-used single herb in the entire Chinese materia medica, appearing in a very large proportion of classical formulas. Its role there is usually not to lead but to harmonise — to moderate harsh herbs, reconcile opposing ones and carry a formula's action. As a tea in its own right it is drunk for sore throats, coughs and a weak digestion. It is also the tea on this site with the most serious safety caveats, and they are set out in full below.

2. Origin and tradition

Liquorice appears in the Shennong Bencao Jing in the superior class and is sometimes called the "grandfather of herbs" or "great harmoniser" for its ubiquity. Classical texts describe it as the peacemaker of a prescription, and its presence in so many formulas reflects that role rather than any single dramatic action of its own.

Two forms are distinguished and used differently. Raw liquorice (sheng gan cao) is cooler and used for heat, toxicity and sore throats. Honey-fried liquorice (zhi gan cao) is warmer and sweeter and used to tonify Spleen qi and support the Heart. Western herbal medicine and the confectionery trade use the related European species Glycyrrhiza glabra, which shares the same active compound and the same safety profile.

3. TCM properties

This page covers liquorice as a home-brewed tea. Liquorice root is also a prescribed herb in Chinese herbal medicine, where it is combined with other herbs and dosed to a diagnosed pattern — a different thing from a kitchen infusion. For the clinical profile, actions in formula and drug interactions, see the gan cao herb page.

Liquorice root (gan cao)

Thermal nature: Neutral
Flavour: Sweet
Channels entered: All twelve channels, particularly Heart, Lung, Spleen, Stomach
Actions: Tonifies Spleen qi; moistens the Lung and stops cough; clears heat and relieves toxicity; moderates and harmonises other herbs; relieves spasm and pain

Liquorice is the only herb in common use said to enter all twelve channels, which is the classical way of describing how universally it combines. Its harmonising role is genuinely functional rather than decorative: it moderates the harshness of strong purgatives, reduces the toxicity of aggressive herbs and makes unpalatable formulas drinkable. Its one classical incompatibility is well known — it is not combined with gan sui, da ji, yuan hua or hai zao.

4. Traditional uses

Sore and irritated throats

Raw liquorice's sweet, moistening, heat-clearing character makes it one of the classical throat herbs, and it is often combined with honeysuckle or platycodon for this. Its demulcent quality coats and soothes an irritated throat directly. Use it for a few days at a time, not as a standing habit.

Dry and irritating coughs

Liquorice moistens the Lung and eases the spasm of a persistent tickly cough. It appears in a great many classical cough formulas for this reason. As with the throat, it is a short-course measure alongside conventional care, and any cough lasting over three weeks needs medical assessment.

Weak digestion and fatigue

Honey-fried liquorice tonifies Spleen qi, the TCM function underlying appetite, digestion and the energy derived from food. In this role it is used for tiredness, poor appetite and loose stools — almost always within a formula rather than alone, since its action here is supportive rather than leading.

Abdominal cramping and spasm

Liquorice relieves spasm and pain, and the classical pair of liquorice with white peony (Shao Yao Gan Cao Tang) is one of the best-known formulas for cramping pain, whether abdominal or in the calves. That is a prescribed formula rather than a tea, but it illustrates the herb's antispasmodic character.

5. Ingredients

2–3g dried liquorice root slices — a very small amount is enough
300ml water
Optional: 5–6 honeysuckle buds for a sore throat
Optional: a few slices of fresh ginger

Dried liquorice root is sold in slices or sticks by Chinese pharmacies and health-food shops. Choose pieces that are pale yellow inside with a fibrous texture and a strong sweet smell; grey, dull or odourless root is old. Note that most liquorice confectionery and many "liquorice" herbal teabags contain little or no real liquorice root, flavoured instead with anise — check the ingredients if you are drinking it for a reason. Deglycyrrhizinated liquorice (DGL) has the problematic compound removed and does not carry the blood-pressure risk, but it is a supplement rather than a tea.

6. Method

Rinse the slices briefly.
Simmer in 300ml water for 10–15 minutes — the root is woody and needs simmering rather than steeping.
Add honeysuckle or ginger, if using, for the last 3–5 minutes.
Strain and drink warm.
Do not sweeten. It does not need it, and adding sugar to something this sweet is unpleasant.

Keep the quantity small. Liquorice is potent and pleasant-tasting, which is a risky combination — it is easy to drink far more than is sensible precisely because it tastes like a treat rather than a medicine. Two or three grams is a cup's worth.

7. Variations and pairings

With honeysuckle: the classical sore-throat combination, adding strong heat-clearing to liquorice's soothing sweetness.
With ginger: warms the drink and suits a cough with a weak or cold digestion.
With red dates: a gentle qi-supporting combination for tiredness.
As a sweetener for bitter teas: a single small slice makes reishi or other bitter decoctions markedly more drinkable — this is its most practical domestic use.
With mint: a refreshing combination for a hot, dry throat in warm weather.

8. When to drink it

Short courses for a sore, dry or irritated throat
Dry, tickly, spasmodic coughs
As a small addition to soften bitter herbal teas
Occasional support for a weak appetite and digestion

Use it in short courses of a few days — a week or two at most — and not as a daily long-term drink. This is the crucial difference between liquorice and the other teas on this site, and the reason is set out below. If you want something for daily long-term use, choose a different tea.

9. Cautions and contraindications

High blood pressure — the central caution: glycyrrhizin in liquorice causes sodium and water retention and potassium loss, which raises blood pressure. This is a well-documented effect, not a theoretical one, and cases of serious hypertension and low potassium from liquorice consumption are regularly reported. Avoid entirely if you have high blood pressure.
Do not drink daily long-term: problems arise from sustained regular intake rather than the occasional cup. Keep to short courses.
Heart disease and heart failure: avoid, because of the fluid retention and potassium effects.
Kidney disease: avoid.
Low potassium, or medication that lowers it: avoid if you take diuretics, corticosteroids or laxatives, or have any condition causing low potassium. The combination can cause dangerous hypokalaemia.
Digoxin: potassium loss from liquorice increases digoxin toxicity risk. Avoid.
Pregnancy: avoid. Higher liquorice intake in pregnancy has been associated with adverse outcomes in observational studies.
Oestrogen-sensitive conditions: liquorice has mild hormonal activity; take advice if this applies to you.
Warning signs to stop: swelling of the ankles or face, headaches, muscle weakness or cramps, or unusual fatigue. Stop and see a doctor.
Classical incompatibilities: not combined with gan sui, da ji, yuan hua or hai zao in Chinese herbal practice.

10. Frequently asked questions

Is liquorice tea safe?

In small amounts occasionally, for most healthy people, yes. Regularly and in quantity, no — and this is unusually well documented. Glycyrrhizin raises blood pressure and lowers potassium, and serious cases follow sustained heavy consumption. Anyone with high blood pressure, heart or kidney disease, or taking diuretics or digoxin, should avoid it.

How much is too much?

There is no single safe threshold that applies to everyone, and sensitivity varies widely between individuals. The sensible approach is small amounts (2–3g) in short courses of days rather than months, with none at all if any of the cautions above apply to you.

Is Chinese liquorice the same as the sweets?

No. Liquorice confectionery in Britain is mostly sugar, wheat flour and anise flavouring, often with little real liquorice extract. Where it does contain genuine extract, the same blood-pressure caution applies — there are documented cases from eating liquorice sweets.

What is DGL?

Deglycyrrhizinated liquorice, with the glycyrrhizin removed. It avoids the blood-pressure and potassium problems and is used for digestive complaints, but it is a processed supplement rather than a tea, and it lacks liquorice's traditional harmonising action.

Why is it in so many Chinese formulas?

Because it harmonises. It moderates harsh herbs, reduces toxicity, reconciles warming and cooling ingredients and improves taste. In a formula it is usually present in a small amount for that role, which is quite different from drinking it on its own as a tea.