This formula is derived from the Treatise on the Spleen and Stomach, and consists of eight herbs: Astragalus, Radix et Rhizoma Ginseng, Atractylodes Macrocephalae, Radix Angelicae Sinensis, Pericarpium Citri Reticulatae, Radix et Rhizoma Bupleuri, Radix et Rhizoma Glycyrrhizae. According to the principle of “ruler, minister, adjuvant and herbalist”, Astragalus is the ruler herb in this formula; Atractylodes macrocephala, Radix et Rhizoma Ginseng or Radix Codonopsis pilosulae and Radix et Rhizoma Glycyrrhizae are the minister herbs; Chen Pi and Radix Angelicae Sinensis are the adjuvant herbs; Chai Hu and Radix et Rhizoma Glycyrrhizae are the herbs. The reason for this formula is that the creator of the sutra formula, Li Donghuan, believed that some patients with spleen and stomach deficiency were caused by deficiency of lung qi, so he chose Huang Qi as the ruler herb to strengthen lung qi. Among the principal herbs, ginseng nourishes the vital energy and strengthens the spleen; licorice harmonizes the middle and benefits the spleen; and atractylodes dries dampness and strengthens the spleen, so these three are used in combination with Huang Qi to treat both the symptoms and the root. In addition, Radix Angelicae Sinensis harmonizes blood and nourishes Yin, while Chen Pi moves Qi, broadens the middle and directs stagnation, and is used to relieve malnutrition and indigestion caused by weakness of the spleen and stomach, playing a complementary treatment effect. It is complemented by Chai Hu and Sheng Ma, which help to promote the lowering of Yang Qi and harmonize the spleen and stomach. In addition, the properties and flavors of the constituent drugs of Tonic Zhong Yi Qi Tang have their own unique characteristics. Astragalus membranaceus is mild and sweet, ginseng is mild and sweet, atractylodes macrocephala is mild and sweet, angelica is mild and pungent, orange peel is mild and bitter, asclepias are mild and slightly bitter, chai hu is mild and slightly bitter, and licorice is slightly bitter. As can be seen from the above, the smell of the medicine used in tonifying Zhong Yi Qi Tang is mainly sweet and warm, slightly supplemented with pungent taste.