Shaoyin disease, characterized by cold extremities (Jue Ni), diarrhea with a sensation of heaviness in the lower rectum. If the patient also presents with cough, palpitations, difficulty in urination, or abdominal pain, Si Ni San (Four Counterflow Powder) is the primary formula to govern it.

The four limbs are the root of all Yang meridians. When Yang Qi fails to reach the four limbs, Jue Ni (cold extremities) occurs; thus, cold extremities mostly belong to Yin syndromes. However, here the presence of diarrhea with rectal heaviness indicates that Yang pathogenic factors have sunk into the Yin. Yang is constrained internally while Yin manifests externally, resulting in the failure of Yin and Yang pulse energies to connect smoothly. Therefore, the view that hand-foot coldness constitutes Re Jue (Heat Jue) and limb coldness constitutes Han Jue (Cold Jue) is also forced and inaccurate. The clause lacks a principal syndrome, consisting entirely of conditional symptoms (Huo Ran Zheng); there must be missing text after the term "Si Ni" (Four Counterflow). By moving the four characters "Xie Li Xia Zhong" (diarrhea with rectal heaviness) to follow "Si Ni," this formula then has a clear structure. Cough, diarrhea, and difficulty in urination correspond to Xiao Qing Long Tang (Minor Green Dragon Decoction) syndrome; cold extremities with palpitations correspond to Fu Ling Gan Cao Tang (Poria and Licorice Decoction) syndrome; cough, diarrhea, abdominal pain, and difficulty in urination correspond to Zhen Wu Tang (True Warrior Decoction) syndrome. These various conditions are caused by water qi pathology. The reason for not employing sweating and diuresis methods is precisely due to "diarrhea with rectal heaviness." The reason for not using Bai Tou Weng Tang (Belamcanda Root Decoction) for "diarrhea with rectal heaviness" is due to the presence of "cold extremities." This represents a dysfunction of the Shaoyin pivot mechanism, leading to multiple conditional symptoms. Thus, four herbs are selected to dissipate the heat pathogen causing cold extremities, and modifications are made according to symptoms to treat the conditional syndromes. This is a purgative formula for Shaoyin Qi-level disorders, exemplifying the principle that "Jue syndromes should be treated with purgation."

Si Ni San (Four Counterflow Powder):
Zhi Gan Cao (Roasted Glycyrrhizae Radix et Rhizoma) | Zhi Shi (Immature Bitter Orange Fruit) | Chai Hu (Bupleuri Radix) | Shao Yao (Peony Root)

These four ingredients, each taken in ten parts, are crushed and sifted. They are mixed with white rice decoction and administered as one Fang Cun Bi (a measure approx. 27ml) per dose, three times daily. For cough, add Wu Wei Zi (Schisandrae Fructus) and Gan Jiang (Dried Ginger) each in five parts; this also treats diarrhea. For palpitations, add Gui Zhi (Cinnamomi Ramulus) in five parts. For difficulty in urination, add Fu Ling (Poria) in five parts. For abdominal pain, add one Pao Fu Zi (Prepared Aconiti Lateralis Radix), roasted until cracked. For diarrhea with rectal heaviness, first boil Xie Bai (Allii Macrostemonis Bulbus) in five sheng of water with three sheng of the herb, reduce to three sheng, strain, then add three Fang Cun Bi of the powder to the decoction, boil again to obtain one and a half sheng, and divide into two warm doses.

This formula imitates the purgative method of Da Chai Hu Tang (Major Bupleurum Decoction). Since Shaoyin serves as the Yin pivot, Huang Qin (Scutellariae Radix)'s bitter cold nature and Sheng Jiang (Fresh Ginger) and Ban Xia (Pinelliae Tuber)'s acrid dispersing properties are removed; Gan Cao (Licorice Root) replaces Da Zao (Jujubae Fructus), which holds profound significance. However, a dose of one Fang Cun Bi may likely be insufficient. In Shaoyang syndrome, palpitations under the heart are treated by adding Fu Ling (Poria); here, Gui Zhi (Cinnamomi Ramulus) is added. In Shaoyang syndrome, abdominal pain is treated by adding Shao Yao (Peony Root); here, Fu Zi (Aconite Root) is added. Although their methods differ in Yin and Yang, they may not be suitable for patients with "diarrhea with rectal heaviness." Xie Bai (Allii Macrostemonis Bulbus) is slippery in nature and can drain stagnation of Yin and Yang Qi in the Lower Jiao, but its acrid-warm property is too intense, and its pungent odor is overwhelming. Using three sheng at once, yet only adding three Fang Cun Bi of powder, results in tasting only the Xie Bai rather than the medicinal flavor. Moreover, while other additions use five parts, why is there such a disparity between one piece of Fu Zi (Aconite Root) and three sheng of Xie Bai (Allii Macrostemonis Bulbus)? This discrepancy inevitably raises doubts about errors in Wang Shuhe's compilation.