Key Takeaways
- Licorice (甘草, Gan Cao) is sweet and neutral — called the "National Elder" of herbs because it appears in over half of all traditional formulas, where it harmonizes, moderates, and enhances the actions of other herbs.
- It tonifies Spleen Qi, clears heat and resolves toxicity, relieves cough and sore throat, and relaxes spasms and cramps — making it one of the most versatile herbs in the materia medica.
- There are three forms: raw licorice (clears heat and toxicity), honey-fried licorice (tonifies Qi and relaxes spasms), and regular dried licorice (general harmonizing).
- Modern research confirms licorice has anti-inflammatory, antiviral, and antispasmodic effects — but also warns of pseudoaldosteronism (sodium retention, potassium loss, high blood pressure) from long-term high-dose use.
- Precautions: long-term high-dose use can cause hypertension, edema, and potassium loss; avoid in hypertension, heart disease, kidney disease, and with certain medications.
Quick Answer: Licorice (Gan Cao) is the "National Elder" of TCM herbs — sweet and neutral, it harmonizes and moderates other herbs in over half of all formulas. It also tonifies Spleen Qi, clears heat and toxicity, soothes sore throat and cough, and relieves spasms. Typical dose: 1.5 to 9 g in decoction. Avoid long-term high doses (blood pressure, potassium loss risk).
1. Properties and Classification
Licorice root (甘草, Gan Cao) — the dried root and stolon of Glycyrrhiza uralensis — is one of the most important and widely used herbs in the Chinese materia medica. The Bencao Gangmu (Compendium of Materia Medica, 1578) calls it the "National Elder" (国老, Guolao), a title of deep respect reflecting its senior, harmonizing position among all herbs. Its Chinese name, Gan Cao, means "sweet herb" — and that sweetness is the key to its versatility.
In TCM classification, licorice has the following properties:
| Property | Detail |
|---|---|
| Nature | Neutral (平) — slightly warm in honey-fried form |
| Flavor | Sweet (甘) |
| Channel affinities | Heart, Lung, Spleen, Stomach (all twelve channels) |
| Key actions | Tonifies Spleen Qi, moistens Lung, clears heat and toxicity, relieves cough and sore throat, relaxes spasms and cramps, harmonizes and moderates other herbs |
What makes licorice extraordinary is its harmonizing function. In TCM herbal formulas, when multiple herbs are combined, licorice is often added to moderate and harmonize the actions of the other herbs — reducing toxicity, softening harsh effects, and helping the formula work together as a unified whole. This is why it appears in over half of all traditional Chinese herbal formulas — more than any other single herb. For the foundational understanding of the Spleen, see our Spleen TCM functions guide.
2. Three Forms of Licorice
Like rehmannia, licorice undergoes different processing to serve different purposes. Understanding these forms is important for proper use.
| Form | Processing | Primary Action |
|---|---|---|
| Sheng Gan Cao (raw licorice) | Dried without further processing | Clears heat, resolves toxicity, soothes throat (preferred for sore throat, heat, and toxicity) |
| Zhi Gan Cao (honey-fried licorice) | Stir-fried with honey until golden | Tonifies Spleen Qi, relaxes spasms, moistens Lung (preferred for Qi deficiency, cramps, cough) |
| Regular dried licorice | Standard dried root slices | General harmonizing; balances formulas (most common form) |
The honey-frying process (paozhi) makes licorice warmer and more tonifying, enhancing its Spleen Qi-strengthening and spasm-relieving properties. Raw licorice retains more of its heat-clearing and toxicity-resolving properties. For sore throat and heat patterns, choose raw licorice; for Qi deficiency and cramps, choose honey-fried.
3. Traditional Uses
Licorice has six primary traditional uses, reflecting its remarkable versatility.
Harmonizing and Moderating Other Herbs
This is licorice's most common role. In multi-herb formulas, licorice is added to moderate the harsh effects of other herbs, reduce their toxicity, and help them work together synergistically. For example, in Mahuang Tang (Ephedra Decoction), licorice moderates the harsh, sweat-inducing effects of Ephedra. In Si Jun Zi Tang (Four Gentlemen Decoction), it harmonizes and completes the Spleen Qi tonifying formula. This is why licorice appears in over half of all traditional formulas.
Tonifying Spleen Qi
As a sweet, neutral herb that enters the Spleen channel, licorice tonifies Spleen Qi — for fatigue, poor appetite, loose stools, and shortness of breath. While not as strong as Ginseng or Astragalus, it supports Spleen function and is a key ingredient in Si Jun Zi Tang alongside Ginseng, Atractylodes, and Poria.
Clearing Heat and Resolving Toxicity
Raw licorice clears heat and resolves toxicity — useful for sore throat, mouth ulcers, skin infections, and food or drug poisoning. It is included in formulas like Gan Jie Tang (Licorice and Platycodon Decoction) for sore throat and Pu Ji Xiao Du Yin (Universal Relief Decoction to Eliminate Toxin) for infections.
Relieving Cough and Sore Throat
Licorice is one of the most effective herbs for cough and sore throat. It moistens the Lung, relieves coughing, and soothes the throat. A simple licorice tea is a traditional home remedy for mild sore throat, and licorice appears in many cough formulas. See our licorice tea guide.
Relaxing Spasms and Cramps
Licorice relaxes smooth muscle spasms — making it useful for abdominal cramps, leg cramps, and muscle tension. The classic formula Shao Yao Gan Cao Tang (Peony and Licorice Decoction) uses a large dose of licorice with White Peony to relieve spasms and cramps, particularly for calf cramps and abdominal pain.
Acting as a Channel Guide
In some formulas, licorice serves as a "channel guide" — a small amount (often 1.5 to 3 grams) added to direct the actions of other herbs to specific channels or organs. For example, in formulas targeting the Heart, licorice can help guide other herbs to the Heart channel.
Li Shizhen, in the Bencao Gangmu, described licorice as the "National Elder" (Guolao) — a title reserved for the most respected senior ministers in ancient China. The name reflects licorice's unique position: it is not the strongest herb, nor the most dramatic in effect, but it is the most reliable, versatile, and harmonizing. Like a wise elder who mediates disputes and brings people together, licorice mediates between herbs, reduces their conflicts, and helps them work as one. This is why it appears in more formulas than any other herb.
4. Modern Research
Modern pharmacological research has identified several active compounds in licorice, most notably glycyrrhizin (glycyrrhizic acid), glycyrrhetinic acid, liquiritin, and flavonoids. The most studied effects are:
- Anti-inflammatory: glycyrrhetinic acid has corticosteroid-like anti-inflammatory effects, supporting licorice's traditional use for sore throat, skin inflammation, and toxicity.
- Antiviral: glycyrrhizin has shown antiviral activity against several viruses in laboratory studies, supporting the traditional use for toxicity and infection.
- Antispasmodic: licorice flavonoids have been shown to relax smooth muscle, supporting the traditional use for cramps and spasms.
- Expectorant and cough-suppressing: licorice has demonstrated the ability to promote mucus secretion and suppress cough reflex, aligning with its traditional use for cough.
- Adrenal support: glycyrrhizin appears to inhibit the breakdown of cortisol, potentially supporting adrenal function — which may explain both its anti-inflammatory effects and the risk of pseudoaldosteronism.
The most important caution from modern research: glycyrrhizin can cause pseudoaldosteronism — sodium and water retention, potassium loss, and elevated blood pressure — especially with long-term or high-dose use. This is the single most important safety consideration for licorice.
5. Dosage and Preparation
Licorice is used in a wide range of doses depending on its role in the formula. As a harmonizer, small doses suffice; as a primary herb for spasms or toxicity, larger doses are used.
| Use | Typical Daily Dose | Preparation |
|---|---|---|
| As formula harmonizer | 1.5 to 3 grams | Added to multi-herb decoction; simmer 10 to 20 minutes |
| For Spleen Qi tonification | 3 to 6 grams | Use honey-fried form; simmer in decoction |
| For sore throat and cough | 3 to 6 grams | Use raw licorice; simmer as tea or in decoction |
| For spasms and cramps | 6 to 9 grams (up to 15 g) | Use honey-fried form; simmer in decoction with White Peony |
| As tea | 3 grams | Steep in hot water for 10 minutes; drink for sore throat |
Cooking with Licorice
Licorice is sweet and pleasant in flavor, making it easy to incorporate into food therapy and herbal teas. A simple licorice tea — 3 grams of licorice slices steeped in hot water for 10 minutes — is a traditional home remedy for mild sore throat, dry cough, and mild digestive discomfort. Licorice is also added to soups, stews, and congees to enhance flavor and harmonize the other ingredients. See our licorice tea guide for recipes.
Pairing with Other Herbs
Licorice is the ultimate team player and is paired with almost every herb in the materia medica:
- With Ginseng (Renshen), Atractylodes (Baizhu), and Poria (Fu Ling) — the Four Gentlemen for Spleen Qi (Si Jun Zi Tang).
- With White Peony (Baishao) — relieves spasms and cramps (Shao Yao Gan Cao Tang).
- With Ephedra (Mahuang) — moderates Ephedra's harsh sweating effects (Mahuang Tang).
- With Platycodon (Jiegeng) — soothes throat and resolves phlegm (Gan Jie Tang).
- With Atractylodes (Baizhu) and Poria (Fu Ling) — harmonizes Spleen tonifying formulas.
6. Precautions and Contraindications
While licorice is generally safe in moderate doses for short-term use, it has important safety considerations, especially with long-term or high-dose use.
- Pseudoaldosteronism — the most important precaution. Long-term use of high doses of licorice (especially the glycyrrhizin content) can cause sodium and water retention, potassium loss, high blood pressure, and edema. This is dose-dependent: short-term use of small amounts is generally safe, but daily use of 10+ grams for weeks can cause problems.
- Hypertension — people with high blood pressure should avoid or use licorice very cautiously, as it can raise blood pressure.
- Heart disease and kidney disease — the sodium retention and potassium loss from licorice can be dangerous for people with heart or kidney conditions.
- With medications — licorice may interact with diuretics, digoxin, blood pressure medications, corticosteroids, and blood thinners. Consult your doctor before using licorice if you take any of these.
- Classical incompatibilities — in TCM, licorice is traditionally contraindicated with Euphorbia kansui (Kansui), Peking spurge root (Gansui), Daphne genkwa (Yuanhua), and Sargassum (Hai Zao) — these are the "Eighteen Incompatibilities" (Shi Ba Fan).
- Pregnancy — large doses of licorice should be avoided during pregnancy. Consult a qualified practitioner.
Frequently Asked Questions
What is Licorice (Gan Cao) used for in TCM?
Licorice (Gan Cao) is called the "National Elder" of herbs in TCM because it appears in over half of all traditional formulas. Its primary role is to harmonize and moderate other herbs — reducing toxicity, softening harsh effects, and helping formulas work synergistically. Beyond harmonizing, it also tonifies Spleen Qi (for fatigue, poor appetite), clears heat and resolves toxicity (for sore throat, infections), relieves cough and sore throat, and relaxes spasms and cramps. Its sweet, neutral nature makes it versatile and gentle enough for broad use.
How do you take Licorice — as tea, soup, or supplement?
Licorice is most commonly cooked in decoction (simmered 10 to 20 minutes) or used as part of a multi-herb formula. A typical daily dose is 1.5 to 9 grams, depending on its role — small amounts (1.5 to 3 g) for harmonizing, larger amounts (6 to 9 g) for spasms or toxicity. For sore throat, a simple licorice tea (3 grams steeped in hot water for 10 minutes) is a traditional home remedy. It is also available as powder, tincture, or in patent formulas. Long-term daily use of high doses should be avoided due to the risk of pseudoaldosteronism. See our licorice tea guide for recipes.
Can Licorice help with sore throat and cough?
Yes, licorice is one of the most effective herbs for sore throat and cough in TCM. It clears heat, relieves toxicity, soothes the throat, and moistens the Lungs to stop coughing. Modern research supports these effects — glycyrrhizin has anti-inflammatory and antiviral properties, and licorice flavonoids have been shown to suppress cough reflex and promote mucus secretion. A simple licorice tea (3 grams in hot water) is a traditional home remedy for mild sore throat. For more severe sore throat, licorice is combined with Platycodon (Jiegeng) in formulas like Gan Jie Tang. See our licorice tea guide.
Are there precautions or contraindications for Licorice?
Yes, and this is very important. The most significant precaution is that long-term use of high doses can cause pseudoaldosteronism — sodium and water retention, potassium loss, high blood pressure, and edema — due to the glycyrrhizin content. People with hypertension, heart disease, or kidney disease should avoid or use licorice very cautiously. Licorice may also interact with diuretics, digoxin, blood pressure medications, and corticosteroids — consult your doctor if you take any of these. In TCM, licorice is also traditionally contraindicated with certain herbs (Kansui, Gansui, Yuanhua, Hai Zao) in the "Eighteen Incompatibilities." Short-term use of small amounts is generally safe for most people.
Sources & References
- Huangdi Neijing (Yellow Emperor's Classic of Internal Medicine) — Compiled ~200 BCE
- Bencao Gangmu (Compendium of Materia Medica) — Li Shizhen, 1578 CE
- WHO Standard Terminology on Traditional Medicine — World Health Organization, 2007
- Chinese Pharmacopoeia — China Medical Science Press
- Shennong Bencao Jing (Divine Farmer's Materia Medica) — Compiled ~200-250 CE
References include classical TCM texts, peer-reviewed pharmacological research, and guidelines from WHO, NCCIH, and other health authorities. This article is for educational purposes and does not constitute medical advice.
This article is for educational and informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Licorice is a traditional wellness tonic, not a medical treatment. Long-term use of high doses of licorice can cause pseudoaldosteronism (sodium retention, potassium loss, high blood pressure, edema). If you have hypertension, heart disease, or kidney disease, or take medication (especially diuretics, digoxin, or blood pressure medication), consult your healthcare provider and a licensed TCM practitioner before using licorice. Read our full disclaimer →
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