Zhi Gan Cao 炙甘草 — Chinese Herbal Medicine

Zhi Gan Cao (炙甘草) At a Glance

• Herb: Zhi Gan Cao
• Chinese name: 炙甘草 (Zhi Gan Cao)
• Latin name: Radix Glycyrrhizae Praeparata
• Nature: Neutral
• Taste: Sweet
• Meridian: Lung
• Category: Tonify the Qi

Zhi Gan Cao — honey-fried licorice root — is one of the most widely employed herbs in classical Chinese medicine, valued for its ability to tonify Qi and moderate the actions of other medicinals within a formula. The honey preparation deepens its sweet nature, making it especially effective for strengthening the Spleen, nourishing the Heart, and restoring a faint or irregular pulse. As the classical “harmonizer of all medicines,” it appears in hundreds of canonical formulas both as a primary tonic and as an essential moderating ingredient.

Actions & Therapeutic Effects

• Tonifies the Spleen and augments Qi
• Nourishes the Heart and restores the pulse
• Moistens the Lung and stops cough
• Relieves spasm and alleviates pain
• Moderates and harmonizes the properties of other herbs
• Reduces the toxicity and harshness of other medicinals

Clinical Applications in TCM

• Spleen and Stomach Qi deficiency with fatigue, poor appetite, and loose stools — used in Si Jun Zi Tang (四君子汤)
• Heart Qi and Yin deficiency with palpitations, shortness of breath, and intermittent pulse — chief herb in Zhi Gan Cao Tang (炙甘草汤)
• Lung Qi deficiency with chronic cough and scanty breath — combined with Ren Shen and Mai Men Dong
• Abdominal spasm and cramping pain from Qi and Blood deficiency — paired with Bai Shao in Shao Yao Gan Cao Tang (芍药甘草汤)
• Sore throat and heat toxin — raw Gan Cao form used; honey-fried version supports recovery phase
• Qi and Blood dual deficiency — combined with Dang Gui and Ren Shen in restorative compound formulas

Precautions & Safety

• Standard dosage: 2–10 g per day in decoction; up to 30–60 g when used as chief herb in Zhi Gan Cao Tang
• Prolonged or high-dose use may cause pseudoaldosteronism: hypertension, edema, and hypokalemia
• Contraindicated in patterns of Dampness obstruction, Phlegm accumulation, or abdominal fullness and distension
• Use with caution in patients with pre-existing hypertension, renal insufficiency, or concurrent diuretic therapy
• Classical incompatibilities (十八反): contraindicated with Gan Sui, Yuan Hua, Da Ji, and Hai Zao

Classical TCM Formulas

• Zhi Gan Cao Tang (炙甘草汤): Zhi Gan Cao, Sheng Jiang, Ren Shen, Sheng Di Huang, Gui Zhi, E Jiao, Mai Men Dong, Ma Zi Ren, Da Zao, wine — nourishes Heart Qi-Yin for arrhythmia. Source: Shang Han Lun.
• Gui Zhi Gan Cao Tang (桂枝甘草汤): Gui Zhi, Zhi Gan Cao — warms Heart Yang. Source: Shang Han Lun.
• Shao Yao Gan Cao Tang (芍药甘草汤) with Zhi Gan Cao for milder, more tonifying action.

Herb Combinations

• Zhi Gan Cao (炙甘草) + Ren Shen (人参) + Da Zao (大枣) + Sheng Jiang (生姜): the foundational Spleen-Stomach tonifying quartet for Qi deficiency.
• Zhi Gan Cao (炙甘草) + Gui Zhi (桂枝): the Gui Zhi Gan Cao Tang pair — warms and unblocks Heart Yang for palpitations.
• Zhi Gan Cao (炙甘草) + Sheng Di Huang (生地黄) + Mai Men Dong (麦门冬): the Zhi Gan Cao Tang approach — nourishes Heart Yin and Qi for arrhythmia.

Pharmacology & Research

Glycyrrhizin (triterpene saponin): anti-inflammatory, adrenocorticoid-like effect, antiviral activity.
Liquiritin (flavonoid): antispasmodic, antioxidant, and hepatoprotective properties.
Isoliquiritigenin: cardioprotective and anti-arrhythmic action supporting use in pulse-restoring formulas.
Polysaccharides: immunomodulatory and adaptogenic support underlying Qi tonification effects.

Classical Descriptions

• “Zhi Gan Cao governs the five exhaustions and seven injuries, and harmonizes all medicines.” — Shen Nong Ben Cao Jing (神农本草经, Divine Husbandman’s Classic of the Materia Medica)