Niuxi Wan (Achyranthes Pill) for Treating Flaccidity Syndrome According to Li Dongyuan
Niuxi Wan (Achyranthes Pill) comes from Li Dongyuan's Essentials of Practical Methods (Huofa Jiyao). Its composition is: Niuxi (Achyranthis Bidentatae Radix, wine-soaked), Bixie (Dioscoreae Hypoglaucae Rhizoma), Duzhong (Eucommiae Cortex, fried), Roucongrong (Cistanches Herba, wine-soaked), Tusizi (Cuscutae Semen), Fangfeng (Saposhnikoviae Radix), Huluba (Trigonellae Semen, fried), Buguzhi (Psoraleae Fructus), Shayuanzi (Astragali Complanati Semen), and Baijili (Tribuli Fructus), in equal amounts; and Rougui (Cinnamomi Cortex), in half a portion. Preparation: grind the above medicinals together into a fine powder, cook pig kidneys in wine, and form into pills the size of a parasol-tree seed (about 6–9 mm in diameter). Take 50–70 pills each time, delivered with warm wine on an empty stomach, 1–2 times daily.
Niuxi Wan mainly treats "damage to the liver and kidneys, bone flaccidity such that the patient cannot rise from the bed" and "relaxed sinews that cannot support or hold themselves." For such patients, Li Dongyuan held that one should "supplement essence and moderate the middle"; hence the formula focuses on tonifying the liver and kidneys. It uses common liver- and kidney-tonifying herbs such as Niuxi, Duzhong, Roucongrong, Tusizi, Huluba, Buguzhi, and Shayuanzi as the main ingredients, assisted by Fangfeng to dispel cold and stop pain, and Baijili to pacify the liver, subdue yang, invigorate blood, and unblock the channels. It further includes Bixie, a commonly used herb for wind-damp bi pain and inhibited joint movement. For the limp, weak "flaccidity syndrome" (weizheng), this formula treats both the root and the manifestation.
The above is an explanation from the perspective of traditional Chinese medicine. From the standpoint of modern pharmacology, several of the herbs in this formula have some effect on repairing damage to the central and peripheral nervous systems, especially Baijili and Bixie. Thus its ability to treat "flaccidity syndrome," whose clinical manifestations are mainly paralysis, also has a certain scientific basis.