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Taste: Acrid (Xin), Bitter (Ku). Nature: Great Cold (Da Han). Indications: Accumulations and masses in the five Zang organs (Wu Zang Ji Ju), chronic fever (Jiu Re), gastric closure (Wei Bi), expelling pathogenic factors (Chu Xie Qi), breaking stagnant blood (Po Liu Xue), phlegm-dampness and solid excretions knotting in the abdomen (Fu Zhong Tan Shi Jie Bo), unblocking meridians and collaterals (Tong Jing Mai), promoting urination and defecation as well as menstruation (Li Da Xiao Bian Ji Yue Shui), breaking the five types of strangury (Po Wu Lin), eliminating the old and generating the new (Tui Chen Zhi Xin). It is generated from Glauber's salt crude (Puxiao).

Shiwei (*Pyrrosiae Folium*) serves as its guiding herb (Shi), and it fears Maijujiang. According to records, the *Shennong Bencao Jing* does not list Mangxiao, only Xiaoshi (Niter/Xiaoshi), merely naming it Mangxiao. Later famous physicians recorded this separately, stating that its therapeutic effects are identical to those of Xiaoshi, leading to suspicion that they are the same substance. Historically produced in Ningzhou, it was yellowish-white with large granules, possessing an extremely acrid and bitter taste. Recently, due to the interruption of routes to Ningzhou, production has ceased. Currently, physicians mostly use the boiled and refined product, which is pure white, fine-grained, but less potent in taste.

The text states it is generated from Puxiao, implying that artificial refinement is also acceptable. Furthermore, Huangfu Shian (Huangfu Mi) generally discussed the dispersal of Xiaoshi saying: "If Puxiao is unavailable, Xiaoshi can be used. It grows on the shady side of mountains and is the gall of salt. Take Shipi (Stone Spleen) and Xiaoshi, boil them in water; from one hu (a unit of volume), three dou are obtained. It is pure white like snow, dissolves immediately when thrown into water, hence named Xiaoshi. Its taste is bitter, non-toxic. It treats thirst-heat in the middle jiao, stops irritability and fullness, and is harvested in March at Chishan. Puxiao also grows on the shady side of mountains; where there is salty, bitter water, Puxiao grows on the sunny side. Its taste is bitter, non-toxic. It treats abdominal fullness, nourishes the stomach and aids digestion, expels pathogens, and also dissolves in water. Its therapeutic effects differ slightly from Xiaoshi." Based on this description, Mangxiao is boiled together to become true Xiaoshi, but it remains unknown what Shipi is. The Materia Medica mentions Shipi and Shipei (Stone Lung), yet no one recognizes them. Since Huangfu Mi was from Anding and knowledgeable in medicine and pharmacology, he might have detailed explanations. To refine Puxiao into Mangxiao, pour hot water over Puxiao, collect the clear juice, boil it until reduced by half, pour it into a wooden basin, and let it stand overnight until formed. It resembles white quartzite and involves six processes. During production, it is taboo to have unrelated people watching. Currently, people in Yizhou refine Fanshi (Alum/Fanshi) to imitate Xiaoshi; it is extremely soft and white, but retains the taste of Fanshi. Kong's formula for dispersal also states: "Boil and refine Xiaoshi until boiling and the juice is exhausted." In this case, Xiaoshi still contains juice. Now, practitioners of immortality arts require it because it can melt other stones, making it the primary application in theory.

[Strict Examination] Ancient prescriptions from the Jin and Song dynasties mostly used Xiaoshi and rarely used Mangxiao. Modern physicians only use Mangxiao and seldom mention Xiaoshi. Could it be that ancients were ignorant of Mangxiao? The *Bencao Jing* states it is generated from Puxiao. Puxiao is also known as Xiaoshi Pu, and Xiaoshi is also known as Mangxiao. Since the principle is clear, it should not be listed redundantly.