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Poria (Fuling, 18 zhu) Polyporus (Zhuling, 18 zhu) Alisma (Zexie, 1 liang 6 zhu) Atractylodes Macrocephala (Baizhu, 18 zhu) Cinnamon Twig (Guizhi, half liang, peeled)
The above five herbs are ground into powder. Mix with rice water and administer one fangcun bi (a square-inch measure) per dose, three times daily. Drink plenty of warm water after administration; recovery is indicated by sweating.

In Taiyang disease (Taiyang syndrome), if sweating occurs accompanied by thirst, Wuling San (Five-Ingredient Powder with Poria) is the primary formula. If there is no thirst, Linggui Gancao Tang (Poria, Cinnamon Twig, Licorice, and Ginger Decoction) is the primary formula.
After sweating in Taiyang disease, Yang Qi deficiency causes dampness to move turbulently, while the Ministerial Fire and Sovereign Fire float upward, resulting in dryness and thirst. This thirst indicates that the damp pathogen is relatively severe, hence the use of Wuling San. The absence of thirst indicates that the damp pathogen is lighter, hence the use of Linggui Gancao Tang. This formula drains water-dampness and soothes the Liver Wood, harmonizes the Middle Jiao and strengthens the Spleen Earth, preventing dampness from moving turbulently and generating water retention.

Poria (Fuling, 2 liang) Cinnamon Twig (Guizhi, 2 liang) Fresh Ginger (Shengjiang, 2 liang) Licorice Root (Gancao, 1 liang, honey-fried)
The above four herbs are decocted in four sheng of water until two sheng remain. Strain the dregs and divide into three warm doses.

When the disease is in the Yang aspect, it should be resolved through sweating. However, if cold water is sprayed or poured over the body, the internal heat is suppressed by the cold water and cannot dissipate, leading to increased irritability and gooseflesh on the skin. The patient may desire to drink water but actually feels no thirst. In this case, Wenli San (Clam Shell Powder) should be administered. If the condition does not improve, Wuling San (Five-Ingredient Powder with Poria) should be given. If it is a Cold-Excess Jie-Xiong (Chest Binding) syndrome without heat signs, Sanwu Xiaoxin Tang (Three-Ingredient Minor Chest-Expelling Decoction) is indicated (see Taiyang Chapter 117); Baisan (White Powder) may also be used.
The pathology of Wuling San syndrome involves water-fluid retention internally, which stagnates and blocks the Yang Qi of the meridians, thereby generating external heat. Since the disease is in the Yang aspect, it should theoretically be resolved by sweating, transforming internal water into sweat, thus curing the disease immediately. However, spraying or pouring cold water causes the pores to close due to cold, trapping the residual exterior heat which cannot escape outward, thereby exacerbating irritability. The Defensive Qi,郁结 (stagnant) and attempting to exit through the pores, is blocked by external cold, causing conflict with the pathogens at the skin level, resulting in granular elevations on the muscle surface. Internal steaming of meridian heat causes irritability, fever, and thirst, prompting a desire to drink; yet, due to internal water retention, the patient actually feels no thirst. Wenli San (Clam Shell Powder) is appropriate here, as Clam Shell promotes diuresis and relieves thirst. If the condition persists, it indicates excessive water abundance and dampness, for which Clam Shell is insufficient; Wuling San (Five-Ingredient Powder with Poria) should still be administered. If Cold Pathogen reverses upward, forming an Excess binding in the chest and diaphragm, with Lung Qi stagnation generating heat but no external heat signs (indicating the exterior pathogen has retreated), Xiaoxin Tang (Minor Chest-Expelling Decoction) is indicated. Huanglian (Coptis Rhizome) and Gualou (Trichosanthes Fruit) clear heat and resolve stagnation, while Banxia (Pinellia Tuber) descends rebellious Qi and opens blockages. Baisan (White Powder) uses Jiegeng (Platycodon Root) and Beimu (Fritillaria Bulb) to clear and descend deficient heat, and Badou (Croton Seed) to warmly break excess cold, inducing vomiting and purging to eliminate the root cause; this may also be administered.