In the formula of Guizhi Tang (Cinnamon Twig Decoction), remove Shaoyao (Paeoniae Radix Alba). Add one Fuzi (Aconiti Lateralis Radix Praeparata), which has been processed, peeled, and broken into eight pieces. The rest follows the previous method.

For Taiyang disease (Disease of the Taiyang/Bladder Channel) presenting with a rapid pulse (Mai Cu) and chest fullness, Guizhi Qushaoyao Tang (Cinnamon Twig Decoction without White Peony Root) is the primary treatment. If there is slight aversion to cold, add Fuzi to the formula that has had Shaoyao removed; Guizhi Qushaoyao Jia Fuzi Tang (Cinnamon Twig Decoction without White Peony Root plus Prepared Aconite Root) is the primary treatment. Note:
The aforementioned rapid pulse and chest fullness result from yang deficiency caused by inappropriate purgation, with yin pathogens clashing in the diaphragm region. At this time, only Ganjiang (Zingiberis Rhizoma) and Guizhi (Cinnamomi Ramulus) should be used to assist yang and scatter pathogens; it is inappropriate to use Shaoyao (Paeoniae Radix Alba) to nourish yin and increase fullness. If there is slight aversion to cold, it indicates that the yin pathogens clashing in the diaphragm are gradually invading beyond the defensive exterior, posing an imminent risk of collapse of yang (Wang Yang). Although the previous formula removes Shaoyao, the power of Ganjiang and Guizhi is still insufficient to fulfill the task of rescuing yang. Therefore, it is necessary to rely on the fierce nature of Fuzi to rapidly reach the defensive exterior, drive out yin pathogens, restore yang, and preemptively prevent the collapse of yang.

In the formula of Guizhi Tang (Cinnamon Twig Decoction), add Houpo (Magnoliae Officinalis Cortex) two liang and Xingren (Armeniacae Semen Amarum) fifty seeds, removing the skin and tips. The rest follows the previous method.
This should also be compared with the syndrome of Gegen Huanglian Huangqin Tang (Kudzu, Coptis, and Scutellaria Decoction). The classic states: For Taiyang disease, if mild wheezing occurs after purgation, it is because the exterior condition remains unresolved. Guizhi Jia Houpo Xingren Tang (Cinnamon Twig Decoction plus Magnolia Bark and Apricot Seed) is the primary treatment. Both belong to the category of wheezing, but one involves the exterior and the other the interior; they must not fail to be distinguished. After purgation, if sweating and wheezing occur, the wheezing will likely be severe, indicating internal heat congestion and fire flaring upward. After purgation, if only mild wheezing occurs, sweating will likely be minimal, indicating exterior pathogen closure and rebellious qi. Since the exterior condition remains unresolved, treatment should still focus on the exterior, primarily using Guizhi to release the exterior, adding Houpo and Xingren to direct rebellious qi downward. Note: Materia Medica records that Houpo and Xingren mainly eliminate phlegm and direct qi downward. Hence it is said, "For patients with chronic wheezing taking Guizhi Tang, adding Houpo and Xingren is excellent."
Yu Jiayan stated: This outlines the main principles for treating wheezing caused by wind pathogens mismanaged by purgation. If wheezing is caused by cold pathogens mismanaged by purgation, Mahuang Shigao Tang (Ephedra and Gypsum Decoction) should be used. This can be inferred analogously.

In the formula of Guizhi Tang (Cinnamon Twig Decoction), add an additional three liang of Shaoyao (Paeoniae Radix Alba), totaling six liang together with the previous amount. The rest follows the method of Guizhi Tang.
Doubling the Shaoyao in the original Guizhi Tang creates a separate decoction name with distinct indications, as ingenious as Guizhi Jia Gui Tang (Cinnamon Twig Decoction plus More Cinnamon Twig). The classic states: Originally suffering from Taiyang disease, if the physician inappropriately uses purgation, resulting in abdominal fullness and intermittent pain, this belongs to Taiyin disease. Guizhi Jia Shaoyao Tang (Cinnamon Twig Decoction plus More White Peony Root) is the primary treatment. For severe excess pain, Guizhi Jia Dahuang Tang (Cinnamon Twig Decoction plus Greater Rhubarb) is the primary treatment. Note: Abdominal fullness and intermittent pain, where the pain is not firm/excess, already harbors the potential for diarrhea. However, investigating the cause reveals that due to inappropriate purgation of Taiyang disease, exterior pathogens have sunk inward and stagnated in the Taiyin system. This is not the fundamental disease of Taiyin organ cold. Therefore, Guizhi is still used to lead the Taiyang pathogens that have sunk into Taiyin outward, while doubling Shaoyao nourishes spleen yin to relieve fullness and pain.
Furthermore, regarding abdominal fullness and intermittent pain, doubling the use of Shaoyao might raise concerns about its overly astringent nature. Cheng Jiaoqian stated: Because the pathogens have sunk deeply, once Guizhi lifts the yang pathogens, one must fear that spleen yin will leak outward along with the exterior-releasing herbs. This is a unique and profound insight.