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Treats conditions where dampness overflows within the interior, and the Spleen and Stomach fail to control it, resulting in accumulation of fluid retention (Ji Yin), chest and diaphragm stuffiness (Pi Ge), and abdominal fullness (Zhong Man).

Cangzhu (Atractylodis Rhizoma, soaked in rice-washing water for seven days) 5 jin; Chenpi (Citri Reticulatae Pericarpium, white pith removed) and Houpo (Magnoliae Officinalis Cortex, stir-fried with ginger juice) each 3 jin; Zhigancao (Glycyrrhizae Radix et Rhizoma Preparatum, honey-fried or roasted) 30 liang. The above are ground into powder. Take 2 qian per dose, administered with ginger decoction, three times daily. Alternatively, decoct with water, taking 5 qian per dose.

[Collected Annotations] Ke Qin stated: *Neijing* states that when Earth Qi is excessive, it is called "Dunfu" (Piled High), manifesting as abdominal fullness; when Earth Qi is deficient, it is called "Beijian" (Low Monitor), manifesting as lingering fullness and blockage. Zhang Zhongjing formulated the Three Chengqi Decoctions to regulate the excessive Earth of the Stomach ("Dunfu"). Li Gao formulated Pingwei San to level the deficient Earth of the Stomach ("Beijian"). "Nourishing the deficient to bring it to balance" does not mean to flatten or reduce it; just as Wendan Tang uses cooling agents to gently harmonize rather than simply applying heat. Later commentators on Materia Medica stated: For Dunfu Earth, Cangzhu is suitable to level it; for Beijian Earth, Baizhu is suitable to nourish it. If one considers Damp Earth as Dunfu, would Dry Earth be considered Beijian? This reflects a failure to examine the meaning that Dunfu belongs to Dryness and Beijian belongs to Dampness, thus failing to understand the principle of Pingwei [Decoction]. Both Cangzhu and Baizhu have sweet and bitter flavors and functions of drying dampness and strengthening the Spleen. When the Spleen is dry, stagnation does not occur, allowing for robust transportation and achieving balance. Secondly, Baizhu is soft and mild, while Cangzhu is fierce and vigorous. Here, Cangzhu is chosen as the Sovereign herb because it excels at inducing sweating and rapidly eliminating dampness. One should not be constrained by the theory of "White tonifies, Red purges" regarding these two herbs. Houpo is red, bitter, and warm; it can assist the "Lesser Fire" to generate Qi, hence it serves as an Assistant. Dampness arises from the failure of Qi movement; when Qi moves, the condition resolves, so Chenpi is added as an Assistant. Sweet flavor enters the Spleen first; when the Spleen is tonified, it transports vigorously, so Zhi Gancao is used as an Envoy. Named Pingwei [San], it is essentially a formula that regulates the Spleen and Stomach, akin to the function of Chengqi formulas! Zhang Jiegou took Zhizhu Tang from *Jingui Yaolue* to make pills. Zhishi (Immature Bitter Orange) is more severe and heavy than Houpo, and lacks Gancao to harmonize it. Even with doubled Baizhu, its draining and reducing power exceeds this formula. Ignorant people consider Baizhu as a tonic and take it for long periods, failing to realize that Zhishi is severe and reducing, and thus unsuitable for prolonged use.