"Muli San" (Oyster Shell Powder) for Night Sweats and Headache
In Qianjin Yaofang (Essential Prescriptions Worth a Thousand Gold) there is a formula called "Muli San" (Oyster Shell Powder), composed of Oyster Shell (muli), Rhizoma Atractylodis Macrocephalae (baizhu) and Radix Saposhnikoviae (fangfeng) in equal parts. Grind together into a powder; each time take 1 qian (3 g), mixed with wine, twice a day. Muli San secures the exterior and stops sweating; it is indicated for night sweats on lying down and wind-vacuity headache.
Muli San and Yupingfeng San (Jade-Breeze Powder) are similar in their composition and in their effects; both are famous sweat-stopping formulas. It is just that Yupingfeng San is composed of Astragalus, Atractylodes and Saposhnikoviae, while Muli San replaces Astragalus with Oyster Shell, which has an astringent sweat-stopping action, making its antiperspirant effect even more marked.
Night sweats with headache are a common aftereffect of infectious disease, for which Western medicine has no particularly effective treatment. Chinese medicine holds that such patients have a weak and unbound exterior with loose interstitial spaces, hence the night sweats. In this formula both Oyster Shell and Atractylodes stop sweating; Saposhnikoviae releases the exterior and dispels evil, while also treating headache. The three together secure the exterior and stop sweating, expel wind and stop pain.
Muli San and Yupingfeng San are similar in composition. The patent medicine made from Yupingfeng San, Yupingfeng granules, is sold in most pharmacies, but Muli San has no ready-made patent form. According to TCM theory, Oyster Shell anchors yang and nourishes yin, which is exactly opposite to Astragalus's action of supplementing yang and securing the exterior, so their tendencies differ. Sweating without cease during the day is yang deficiency failing to secure, whereas night sweats are yin deficiency with effulgent fire and floating yang outward; the two are treated differently and cannot be used interchangeably.