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Puxiao (Raw Glauber's Salt)

Bitter, pungent; cold to very cold; non-toxic. It treats various diseases, eliminates pathogenic factors of cold and heat, expels accumulations in the six fu organs, breaks up firm masses and stagnations, clears heat consolidations from food retention in the stomach, breaks up retained blood and obstructions, resolves stagnant phlegm causing chest fullness, pushes out the old to bring forth the new, and can dissolve seventy-two kinds of minerals. After refining and taking it, one may become light-bodied and achieve immortality. Refined Puxiao is white as silver, possessing properties that are both cold and hot, slippery and astringent, pungent and bitter, salty and sour. It remains unchanged even after being buried in the earth for a thousand years. Those with a bluish-white color are superior; they can be gathered at any time. (It fears Maijujiang.)

Tao Hongjing stated: Currently, it is produced in the former Wenshan Commandery in northern Yizhou, as well as in the borders of Canling County and Xichuan. It grows on mountain cliffs, mostly appearing bluish-white, often mixed with black spots.
Common people select the white and soft variety to use as Xiaoshi (Niter). It should be heated until the liquid boils out, resembling Fanshi (Alum). The "Immortal Classics" only state that Xiaoshi can dissolve other stones. This text also claims it can dissolve stones, suggesting they must be similar, which can be tested. The Tang Dynasty commentary notes: There are two types of this substance, one with longitudinal grain and one without; there is no difference in their use. The white and soft variety is the sprout of Puxiao; it is void and soft with weak potency. When refined into Xiaoshi, the yield is low, and using it as a substitute for Xiaoshi results in significantly inferior efficacy. Current annotations state: It is currently produced in Yizhou. Locals gather it by leaching with water to extract the juice, which is then boiled and refined into Puxiao. Another name is "Xiaoshi Pu." "Xiao" refers to its original form; "Shi" denotes hardness and whiteness; "Pu" means unrefined. Since Mangxiao (Refined Glauber's Salt) and Yingxiao all originate from it, it is called Xiaoshi Pu. That Yingxiao is what is commonly known today as Mayaxiao (Horse Tooth Niter). Ministers Yu Xi et al. carefully noted according to *Yaoxing Lun*: Puxiao is the sovereign herb, bitter and salty, slightly toxic. It can treat abdominal distension, obstruction of urination and defecation, and amenorrhea in women. Ri Huazi stated: It primarily promotes the discharge of pathogens from the five zang organs and hundred diseases, resolves masses, treats epidemic febrile diseases, reduces swelling and toxins, relieves headaches, discharges pus, and moistens hair and nails. When used in decoctions, place Puxiao in the cup first, pour hot medicinal liquid over it, and take.

*Tujing* states: Puxiao grows in the sunny slopes of valleys in Yizhou containing saline water. Xiaoshi grows in valleys in Yizhou and in Wudu, Longxi, and the Western Qiang regions. Mangxiao originates from Puxiao; it is now found throughout the north and south, but those from Xichuan are best. Old theories held that these three substances are of the same species. Initially, the sprouts were harvested, leached with water to obtain juice, and boiled/refined to produce Puxiao, also named Xiaoshi Pu. From within it, Xiaoshi is extracted. Further refining of Puxiao or ground frost produces a hard, white, stone-like substance called Xiaoshi, also known as Mangxiao. Taking Puxiao, leaching it with warm water, refining it until reduced by half, pouring it into a basin, and leaving it overnight yields fine crystals, which is Mangxiao. Although they share one origin and different names, since the refinement methods differ, their therapeutic effects vary. However, *Ben Jing* records them as coming from different places, suspecting they are two distinct things. Current physicians do not trace their origins, simply classifying unrefined, slightly blue-green lumps as Puxiao; refined substances with crystals on top in basins as Mangxiao (also called Panxiao); and the sediment at the bottom of Mangxiao as Xiaoshi. Puxiao has strong potency, Mangxiao is moderate, and Xiaoshi is milder; it is unknown which is authentic. Furthermore, Su Gong stated that ancient formulas from the Jin and Song dynasties used Xiaoshi more frequently and Mangxiao less. Modern physicians use only Mangxiao and rarely mention Xiaoshi, which is incorrect. Zhang Zhongjing’s *Shanghan Fang*: Chengqi Tang and Xianxiong Wan all use Mangxiao. Ge Hong’s *Zhouhou Beiji Fang* uses Mangxiao frequently for Shanghan, Shiqi, and Wenbing. Only for treating undigested raw meat in the chest and diaphragm is Puxiao used. It states that if Puxiao is unavailable, Mangxiao can be substituted. Thus, before the Jin and Song dynasties, Puxiao and Mangxiao were used interchangeably. Also, *Huqia Fang*’s Shizao Tang uses Mangxiao, while Dawuyin Wan uses Xiaoshi. It also states that if Xiaoshi is unavailable, Mangxiao can be used. Thus, during the Liang and Sui periods, Mangxiao and Xiaoshi were used interchangeably. By this reasoning, Puxiao and Xiaoshi are refined, while Mangxiao is crude. Therefore, Tao Hongjing cited Huangfu Mi’s method for refining Xiaoshi: boiling Mangxiao with Shipi to create true Xiaoshi, though Shipi is no longer recognized. He also annotated Fanshi: Raw is called Machi Fan (bluish-white); fully refined is pure white. People in Shu used it as Xiaoshi, indicating that true Xiaoshi was already rare at that time. Consequently, medical texts rarely used it, substituting one for another. If so, although current usage may not identify the true substance, given the similarity in efficacy, general substitution is undoubtedly acceptable. The reason *Ben Jing* recorded different origins for them is likely due to regional differences in refinement techniques (refined vs. crude), necessitating distinction. For example, Xiong and Miwu, Daji and Zekun, are the same plant, yet *Ben Jing* lists different origins, likely because roots and shoots have different geographical preferences, not because they are different entities. Similarly, Puxiao and Xiaoshi listing different origins follows this logic. Comparatively, there is Yingxiao, also derived from Puxiao. It resembles white quartz, having four or five edges, bright white and attractive. Its function is similar to Mangxiao but lacks purgative power and is weaker. It is also called Mayaxiao, named for its shape, and is widely used in recent times. Another method, Jinshi Ling, uses Mayaxiao, Mangxiao, Puxiao, and Xiaoshi in sequence. This method dates to the Tang dynasty; it is unclear how they distinguished them then. Below, there is an entry for Shengxiao: Grows among rocks in western Maozhou. Lumps vary in size, color is bluish-white, rarely used. Current physicians also use a type called Tianxiao, which is finer and better; some suspect this is Yingxiao. Refinement methods are unknown. Southern physicians discuss Xiao differently. One theory states: Materia Medica lists Puxiao, Xiaoshi, and Mangxiao, but not Mayaxiao. Commentaries on these three lack consensus. Some say Mangxiao and Xiaoshi are the same and should not be listed separately. Others argue that leaching Puxiao overnight produces fine crystals, implying it is Mayaxiao. Still others claim Mayaxiao is Yingxiao, meaning they are identical. If Mangxiao is equated with Puxiao, Yingxiao should not appear as a separate origin. Currently, the bodies of various xiao are distinct, making the logic clear, yet such confusion persists. Puxiao is bitter and slightly salty. *Ben Jing* says bitter; *Mingyi Bielu* says pungent, likely confusing it with Xiaoshi. Those from Shu are crystal white like ice and snow; those from inland are dark black. All are brittle and easily crushed. Wind causes them to frost over, becoming powdery. Heating melts them; they can be cast. Boiling with water, Licorice Root, and pig bile reduces volume by half. Pouring into a large basin and soaking with Ninghuai Shi powder overnight yields crystals resembling white quartz, which is Mangxiao. Scrape frost off the ground, refine into salt-like pieces, taste bitter and pungent. Burning leaves no residue, yielding Xiaoshi. It can dissolve metals and stones. Though fearing fire, it can suppress other stones from resisting fire, making it a divine object of heaven and earth. Yaxiao is Mangxiao. There is also Shengxiao, formed without boiling/refining, also from Shu roads, similar to Puxiao but smaller and harder. Although the discussion is detailed, it differs significantly from ancient descriptions and cannot be fully trusted. Zhang Zhongjing’s *Shanghan Lun* treats bladder urgency, lower abdominal fullness, generalized jaundice, black forehead, and heat in the soles, resulting in Heidan (Black Jaundice). Stool will be black, abdomen distended like water, loose stool. This is caused by female exhaustion (Nulao), not water accumulation. Abdominal fullness is difficult to treat; prescribe Xiaoshi Fanshi San. Fry Xiaoshi until yellow, roast Fanzhi until juices run out. Mix equal parts, sieve through double-layer silk, mix with barley gruel, take one cun-bi dose, three times daily. Cover with thick clothing to induce slight sweating. The disease exits via urine and stool; urine becomes normal yellow, stool normal black. Use hulled barley. *Qianjin Fang* uses two parts Xiaoshi and one part Fanzhi. Liu Yuxi’s *Chuanxin Fang* records Stone Mountain Man’s Ganlu Fan: Treats heat congestion, cools the upper jiao, stops vomiting of stagnation. Take Shu Puxiao powder, one large jin, mixed with honey: thirteen liang in winter, twelve liang in spring, summer, autumn. Sift Puxiao powder, mix evenly with white honey. Place in fresh green bamboo segments (half-full max, do not fill completely). Steam inside a rice steamer, ensuring the medicine is surrounded by rice, with empty space above. Do not obstruct the steamer grate. Once rice is cooked, remove while hot, filter through cotton into a porcelain bowl. Stir continuously with a bamboo whisk until solidified. Store in containers. In hot months, soak the bowl in cold water before stirring. Take half to one spoonful after meals or before bed, swallowing slowly. Can also promote bowel movement.

*Shenghui Fang*: Treats persistent headache from epidemic qi. Two liang of Puxiao, pounded and sifted into powder. Mix with raw oil, apply to the vertex. Another formula: Treats restlessness and oppression from Rushi activation and various wind-heat patterns. Half liang of refined Puxiao, finely ground to powder. Take one qian-bi dose mixed with honey water, three to four times daily. *Waitai Miyao*: Miraculous treatment for Houbi (throat obstruction). One liang of Puxiao, hold in mouth and swallow juice slowly; relief occurs instantly. Sun Simiao’s *Shiji*: Treats oral ulcers; hold Puxiao in mouth. *Jianyao Jizhong Fang*: Treats urinary obstruction and bladder heat. Baihua San: Puxiao, amount unspecified, ground to powder. Take two qian-bi doses, mixed with warm fennel wine, taken at any time.

*Yanyi* states: Puxiao is obtained by initial sweeping and single boiling, without further refinement, hence named "raw" (Pu). Its taste is extremely astringent, giving it strong, urgent, and unharmonious properties. It can cure raw cow and horse hides and detect counterfeit gold and silver. Ge Hong used it to purge indigestion from raw meat. In the twelfth lunar month, fill a new clay pot with hot water, add two sheng of Puxiao, stir until dissolved, and hang under the north eaves. Wait for crystals to seep out of the pot, collect with feathers. Mix half a qian-bi dose with human milk, apply externally to eyelids affected by wind-heat toxins, or for swelling and pain on the head, face, and limbs. It works miraculously.