Licorice (Gan Cao)

Overview

Licorice root, Gan Cao, meaning sweet grass, is the most used herb in Chinese medicine: it appears in a large share of classical formulas, where it is called the great harmonizer because it moderates harsh herbs and binds a prescription together. It is neutral to slightly warm, sweet, and enters all twelve meridians. Its sweetness comes from glycyrrhizin, a compound tens of times sweeter than sugar.

Traditional Uses in TCM

• Harmonizing: it reduces the toxicity and harshness of other herbs and coordinates the actions of a formula.
• Cough and sore throat: licorice moistens the lung and throat, and honey-fried licorice is used for dry coughs.
• Spleen support: in qi-tonic formulas like Si Jun Zi Tang it strengthens digestion and energy.
• Ulcers and spasms: it soothes stomach pain and relieves smooth-muscle cramping, often paired with white peony.

How to Use

In decoctions, 2 to 10 grams of sliced root are simmered with the other herbs. At home, a small piece of licorice root or a few slivers in herbal tea adds natural sweetness and soothes the throat. Honey-fried licorice (Zhi Gan Cao) is warmer and used for qi deficiency.

Safety and Cautions

Licorice is safe in normal formula amounts and as occasional tea, but prolonged high doses can raise blood pressure and lower potassium because glycyrrhizin affects sodium and potassium balance. People with hypertension, heart or kidney disease, or taking diuretics should not take concentrated licorice for long periods. WHO-style guidance suggests keeping glycyrrhizin below roughly 100 mg per day for regular use. In TCM it is avoided in cases of fullness and swelling from excess damp, and long-term use is traditionally said to cause water retention.