Library

Clear heat, moisten dryness, and soften hardness.
Pungent, sweet, and cold in nature. It removes excess heat from the stomach and sweeps away accumulated fecal matter in the intestines. It moistens dryness, breaks up accumulations, reduces swelling, and improves vision (when blood-heat is cleared, swelling subsides and vision becomes clear. Wang Ang notes: For persistent diarrhea and dysentery, using Da Huang (Rhubarb) and Yuan Ming Fen (Mirabilite) to push out stagnation can actually stop the diarrhea and dysentery. This is because if the accumulated filth is not cleared, the disease will never be eradicated; this is what the Classics refer to as "treating obstruction with unblocking methods" or "using purgatives for diarrhea"). Piao Xiao (Mirabilite) is dissolved by boiling with Lai Fu (Radish), then decocted with Gan Cao (Licorice Root), and calcined in a jar over fire to remove its salty-cold property, making it yin-containing-yang, with a slightly milder nature. Generally, it can be used as a substitute for Piao Xiao, but it is contraindicated for those with deficient stomach qi and no excess heat. Both are incompatible with Ku Shen (Sophora Root).

Clear heat, nourish yin.
It is the essence of Taiyin, salty, cold, and descending. It treats conditions of excess above and deficiency below, rescues yin and assists yang, and has the merit of supporting critical conditions and reversing adverse states (Zheng Yang Dan is used to treat high fever caused by Shang Han [Cold Damage]; Lai Fu Dan is used to treat heat-induced diarrhea due to latent summer-heat). It originates from salt accumulation areas such as Jie Chi and Tong Tai, formed by the crystallization of saline water. Those that are greenish-white, crystal clear, and have six edges on each flake are considered superior. What is currently used in the market is mostly counterfeit Jiang Shi (Red Hematite).

Heavy, astringent, and consolidating the Large and Small Intestines.
Sweet and warm in nature, thus it tonifies qi, generates flesh, and harmonizes the middle jiao. Sour and astringent, thus it dries dampness (The Lone Journey Formula records: powdered form treats oozing and red swelling in infants' umbilical cords). Stops bleeding and consolidates the lower body (Jing Shu states: After severe diarrhea, when the Large and Small Intestines suffer from collapse due to deficiency, only astringents can consolidate them. Other astringent herbs are light and floating and cannot reach the lower jiao; only Chi Shi Zhi (Red Halloysite) is heavy and astringent, entering directly into the yin aspect of the lower jiao, making it an essential herb for chronic dysentery and abdominal masses. Zhang Zhongjing uses it in Tao Hua Tang [Peach Blossom Decoction], adding Gan Jiang (Dried Ginger) and Jing Mi (Rice)]. It treats intestinal wind with bloody stool, diarrhea and dysentery, metrorrhagia, leukorrhea, spermatorrhea, sores, hemorrhoids, and ulcers; promotes wound closure and tissue regeneration; and induces labor/expulsion of the placenta (Jing Shu states: It can eliminate evil blood; once the evil blood is transformed, there is no obstruction to the fetal sac. Li Dongyuan states: If the placenta fails to descend, astringents can be used to expel it. He also says: While it has a收敛 [astringent/consolidating] ability for the intestines and stomach, it lacks the harsh pushing-down action required to expel the placenta). Those that are fine, smooth, and sticky to the tongue are of good quality. Red enters the blood level, white enters the qi level (Five-colored Shi Zhi corresponds to the five zang organs). Grind into powder and use after water-trituration (shui fei). Incompatible with Yuan Hua (Genkwa Flower). Averse to Da Huang (Rhubarb).