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Gancao (Radix Glycyrrhizae)

Taste: Sweet. Nature: Neutral. Raw use is cold, processed (roasted with honey) use is warm; its action can ascend and descend. It belongs to Yin containing Yang. Non-toxic. Produced in the valleys of Shaanxi province; roots are harvested after autumn. Named "Gancao" because of its sweet taste. Contraindicated with pork; adverse reaction with Yuanzhi (Radix Polygalae). Incompatible with Gansui (Radix Euphorbiae Kansui), Haizao (Thallus Sargassii), Daji (Radix Euphorbiae Pekinensis), and Yuanhua (Flos Genkwa). Enters the Foot-Taiyin Spleen Meridian, Foot-Shaoyin Kidney Meridian, and Foot-Jueyin Liver Meridian. Used with Baizhu (Rhizoma Atractylodis Macrocephalae), Ganqi (Resina Xanthorrhoeae), and Kushen (Cortex Phellodendri) as guiding herbs. Raw Gancao clears heat and purges fire; roasted Gancao warms the middle jiao. Gancao shao (tip) relieves painful dysuria; Gancao jie (node) dissipates carbuncles and sores. Gancao zi (seed) removes chest heat; these three parts should be used raw.

Select robust Gancao stems with prominent transverse rings for use. The skin may be scraped off depending on whether raw or processed form is needed. For Xuanyong (a toxic swelling occurring behind the scrotum and anterior to the anus), single administration causes it to disperse. (For any toxin arising behind the scrotum and anterior to the anus, take 5 qian of Gancao with transverse rings, decoct in wine, and ingest to disperse.) For sore throat, rapid swallowing provides immediate relief. Combined with Jiegeng (Radix Platycodonis), it treats Feiwei (lung atrophy) with simultaneous expectoration of pus and blood; combined with Shengjiang (Rhizoma Zingiberis Recens), it stops dysentery even when white mucus is mixed in stool. For newborn infants, adding Huanglian (Rhizoma Coptidis) to decoct a soup for wiping the mouth is beneficial; for food poisoning, decocting with Heidou (Semen Phaseoli Vulgaris Nigrum) helps. It promotes flesh growth, strengthens the spleen and stomach, tonifies the Triple Burner. It stops thirst, removes irritability, nourishes blood, and directs Qi downward. It resolves the toxicity of all medicines to prevent harm and harmonizes the properties of various herbs to prevent conflict. Later generations revered it, calling it "Guolao" (State Elder). Furthermore, due to its mild nature, it can resolve various acute conditions. Thus, when used with hot medicines, it moderates their heat; when used with cold medicines, it moderates their coldness. For example, in Fuzi Lizhong Tang (Aconite Decoction to Regulate the Middle), users fear the medicinal force might overact upwards; in Tiaowei Chengqi Tang (Regulate the Stomach and Purge the Bowels Decoction), users fear the action might be too rapid downwards. These cases utilize its moderating property, not merely its harmonizing property. In Xiaochaihu Tang (Minor Bupleurum Decoction), there are the cold properties of Chaihu (Radix Bupleuri) and Huangqin (Radix Scutellariae), and the warm properties of Renshen (Radix Ginseng) and Banxia (Rhizoma Pinelliae); adding Gancao for simultaneous decoction achieves true harmony and coordination, which is distinct from mere moderation. In Fengsui Dan (Phoenix Marrow Pill), it serves as a tonic; although it alleviates dampness in the kidney, it essentially benefits the Primordial Yang.

The Classics state: Use sweet to tonify, use sweet to moderate urgency, use sweet to purge excess; this can all be verified. In cases of fullness in the middle jiao, one must fear that sweet flavor may cause distension; thus, it is strictly prohibited to add it. For medicines targeting the lower jiao, because their nature is slow and difficult to reach the destination, they should be used in small amounts. For all types of vomiting, decoction and tasting are also contraindicated. Long-term consumption lightens the body, prolongs life, and delays aging.

(Chen Jiamo) Commentary: The functions of the five flavors are: Bitter goes straight down to purge; Pungent moves horizontally to disperse; Sweet ascends to release; Sour binds and converges; Saline stops and softens hardness. Gancao has the most extreme sweet taste, so it should be described as ascending. Why does the Materia Medica say it directs Qi downward? This is because the sweet flavor possesses ascending, descending, floating, and sinking properties; it can act upward or downward, internally tonifying or purging. Occupying the central position, it embodies all these principles, hence such descriptions.