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Hua Shi (Talcum), possessing the property of lubricating orifices and promoting urination. Its heavy nature drains fire qi, while its light nature releases the muscle layer. It is bland in taste to leach out dampness, sweet in taste to benefit qi and tonify the Spleen and Stomach, and cold in nature to clear heat and descend Heart fire. Because its color is white and enters the Lung meridian, it moves upward to open the Cou Li (pores) and release the exterior (the Lung governs the skin and hair), and moves downward to the Bladder to promote water metabolism. It unblocks the fluids of the Six Fu organs and nine orifices. It is the primary herb for the Foot-Taiyang (Bladder) meridian. It treats summerheat accumulation and heat, vomiting with irritability and thirst, jaundice and edema, Hong Kong foot (podagra) with stranguria (primarily treating stone stranguria), watery diarrhea and dysentery with heat (Liu Yi San added with Red Yeast Rice treats bloody dysentery; added with Dried Ginger treats white dysentery), hematemesis and epistaxis, various sores and toxic swellings. It is a crucial agent for sweeping away heat and removing dampness. It dissipates summerheat, resolves nodules, promotes lactation, and facilitates childbirth (Shizhen said: Talcum lubricates orifices, not limited to urination. Upward opening of Cou Li to release the exterior clears damp-heat from the Upper and Middle Jiao; downward promotion of urination clears damp-heat from the Middle and Lower Jiao. When heat is removed, the Three Jiao becomes tranquil and interior-exterior harmonizes; when dampness is removed, the Lanmen [gate separating clear and turbid] becomes patent and Yin-Yang flows smoothly. The Lanmen separates clear and turbid, located at the lower outlet of the Small Intestine. Hejian's Yi Yuan San treats all diseases of the upper/lower and interior/exterior, embodying this principle. Yi Yuan San, also known as Tian Shui San or Liu Yi San, takes the meaning of "Heaven generates one water, Earth completes six." The formula contains 6 qian of Hua Shi and 1 qian of Gan Cao, optionally adding Chen Sha. Hua Shi treats thirst not by directly stopping it, but by utilizing its orifice-lubricating property to leach out damp-heat, thereby restoring Spleen-Stomach harmony and naturally stopping thirst. If there is no dampness, urination is free, yet thirst persists, it indicates internal dry-heat, requiring moistening. Misuse of this herb will further deplete body fluids and worsen thirst; thus, Wang Haogu considered it an extremely drying agent). White and moist specimens are superior. Shi Wei serves as the guiding herb. It should be combined with Gan Cao (due to its draining nature, Gan Cao is used to harmonize it).

Pu Xiao (Mirabilite crude), also known as Pi Xiao.
Efficacy: Strong purgation, moistening dryness, softening hardness.
Pungency can moisten dryness, saltiness can soften hardness, bitterness can purge downward, and great coldness can eliminate heat. Pu Xiao has a harsh, astringent taste and urgent nature, whereas Mang Xiao (refined Mirabilite) is slightly milder after processing. It can sweep away excess heat in the Three Jiao, intestines, and stomach, pushing out the old to generate the new (Note: Generating the new implies that purging can also have a tonifying effect, similar to Da Huang. This is because if pathogenic factors are not eliminated, healthy Qi cannot recover). It treats Yang hyperactivity disorders, Shanghan (The Classics state: Injury by cold inevitably leads to heat, as cold stagnates and transforms into heat), epidemic dysentery, accumulations and masses, retained blood and phlegm, jaundice and stranguria, scrofula and sores, red eyes and cataracts. It unblocks menstruation and induces abortion (An official in Fengcheng had a cat whose kittens died in the womb, crying desperately. A doctor administered nitrate/niter, and the dead kittens were expelled. Later, a cow was treated similarly and survived. Originally used for humans, it is also effective for animals *Jing Shu* states: Xiao means to dissolve; it can dissolve metals and stones, let alone accumulations in the Zang-Fu organs. Its nature advances relentlessly, described as "nothing hard it does not break, nothing hot it does not sweep." It should not be lightly prescribed unless the disease involves deep-seated heat pathogens and severe obstruction, lest it mistakenly damage the True Yin of the Lower Jiao. Cheng Wuji stated: For heat rampant within, treat with salty-cold; use salty to soften hardness, and cold to eliminate excessive heat. Thus, Zhang Zhongjing's Da Xian Xiong Tang, Da Cheng Qi Tang, and Tiao Wei Cheng Qi Tang all use Mang Xiao to soften hardness and remove excess heat. If the accumulation is not hard, it should not be used. Assisted by bitter herbs, Da Huang is used as a complementary guide. Xu Yuqing stated: Mang Xiao dissolves and disperses, breaking knots and softening hardness. Da Huang pushes and sweeps, moving without staying; thus, the two herbs complement each other as strong purgatives. Wang Haogu stated: Materia Medica records that Mang Xiao induces abortion, yet in pregnancy complicated by Shanghan where purging is indicated, combining it with Da Huang to moisten dryness, soften hardness, and drain heat allows mother and fetus to remain safe. The Classics say: "If there is a cause, there is no injury, nor to the injured," which refers to this. It means the medicine targets the pathology, so neither mother nor fetus suffers)." Niter can soften metals and transform seventy-two types of stones into water. It grows in saline lands, scraped and refined. The substance settling at the bottom is Pu Xiao; the crystalline substance on top with sharp edges is Mang Xiao; the tooth-like crystals are Ma Ya Xiao; placed in wind and sun until moisture evaporates, becoming light and white like powder, it is Feng Hua Xiao. Da Huang serves as the guiding herb (*Ben Jing*, *Bie Lu*: Although Pu Xiao and Xiao Shi are classified as two substances, their flavors and therapeutic actions are roughly similar. Later debates were numerous but inconclusive. Li Shizhen stated: Pu Xiao descends, belonging to Water nature and cold; Xiao Shi used for fireworks, Yan Xiao ascends, belonging to Fire nature and warm. Ang notes: In common usage, niter is never taken for its ascending and warming properties; Li's theory is likely inaccurate).