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Zhang Zhongjing's use of Guizhi (Cinnamon Twig) is not limited to Taiyang disease (diseases caused by pathogenic factors invading the Taiyang channel); even when interior syndromes are already present but the exterior syndrome has not yet resolved, Guizhi is still used. Therefore, in Xiaojianzhong Tang (Minor Construct the Middle Decoction) and Da Fumai Tang (Major Restore Pulse Decoction), despite the presence of cloying and greasy herbs, a single dose of Guizhi is borrowed to dispel residual pathogens; the use of Guizhi in formulas such as Tao Ren Cheng Qi Tang (Peach Kernel Drains the Lower Bowel Decoction), Huanglian Tang (Coptis Decoction), Guizhi Renshen Tang (Cinnamon Twig and Ginseng Decoction), Chaihu Jianggui Tang (Bupleurum, Ginger, and Cinnamon Twig Decoction), Danggui Sini Tang (Angelica Sinensis Cold-Reversal Decoction), and Wumei Wan (Mume Pill) all follow this principle. Most notably, in the chapters on Yangming disease and Taiyin disease, there are discussions stating that "if a floating pulse is present, Guizhi Tang should be appropriate." This shows that even in the absence of obvious exterior symptoms, if an exterior-type pulse appears, Guizhi should still be used. The reason for this is that an exterior-type pulse indicates that Qi is connected to the exterior, which is similar to the state where the exterior syndrome has not resolved; in the absence of exterior symptoms, treatment must adapt to the specific pathology observed. Modern practitioners who rigidly confine Guizhi to the Taiyang channel ultimately fail to understand its principles. Although Zhang Zhongjing's intentions were profound, careful reading reveals the principles within the text, leaving traces to be followed; this is why he remains the teacher of medicine for all generations.

When responsibilities are shared, authority is divided; when responsibility is singular, authority is concentrated. When authority is divided, efficacy is dispersed; when authority is concentrated, efficacy is focused. "Shared" means the medicinal action is jointly undertaken by the primary herb and others; "concentrated" means other herbs are directed by the primary herb. In Guizhi Tang, both Guizhi (Cinnamon Twig) and Shaoyao (White Peony Root) are used in equal amounts of three liang; thus, Guizhi independently disperses wind, while Shaoyao independently consolidates sweat, without relying on each other. This is what is meant by shared responsibility, divided authority, and dispersed efficacy. In this formula (Xinjiasheng Tang/Modified New Addition Decoction), Guizhi is used in three liang, while Shaoyao is used in four liang. Here, Shaoyao directs Guizhi; although Guizhi possesses the ability to disperse wind, it merely utilizes its acrid-warm nature to facilitate penetration, assisting Shaoyao in unblocking blood stasis and bi-syndrome, rather than displaying its own strengths alone. This is what is meant by singular responsibility, concentrated authority, and focused efficacy. The rationale for adding Shengjiang (Fresh Ginger) can be inferred analogously. This discussion addresses body pain occurring after sweating, which clearly belongs to the pattern of fluid depletion following sweating, leading to blood and Qi stagnation and obstruction. Since fluids and blood share the same origin, treatment proceeds from the perspective of Blood Bi (Blood Obstruction). Both Shaoyao and Shengjiang treat Blood Bi, hence their dosages are specifically increased. Because fluids are depleted, Renshen (Ginseng) is added, consistent with the pathological meaning of Baihu Jia Renshen Tang (White Tiger Plus Ginseng Decoction). How do we know this body pain is due to Blood Bi? It is known through the deep and fine pulse. In the case of Gualou Guizhi Tang (Trichosanthes Root and Cinnamon Twig Decoction), a deep and fine pulse is also mentioned, and the etiology is likewise fluid depletion; using that case to illuminate this one makes it clear.