通、利窍行水、体重、泻火。
淡渗湿。滑利窍。寒泻热。色白入肺。清其化源。而下走膀胱以利水。通六腑九窍津液。
为
足太阳经本药。（膀胱。）治中暑积热。呕吐烦渴。（非实止渴、取其利窍、渗去湿热、则脾
胃中和、而渴自止耳、若无湿、小便利而渴者、内有燥热、宜滋润、或误服此、则愈亡其津
液、而渴转甚矣、故好古以为至燥之剂。）黄胆水肿。香港脚淋闭。（偏主石淋。）水泻热痢。（六
干姜、治白痢。）吐血衄血。诸疮肿毒。为荡热除湿之要药。（时珍
曰∶滑石上利毛腠之窍、是除中上之湿热、下利精溺之窍、是除中下之湿热、湿热去、则三
焦宁而表里和、阑门通而阴阳利矣、河间益元散、治表里上下诸病、盖是此意、益元散、一
名天水散、一名六一散、取天一生水地六成之之义也、滑石六钱、甘草一钱、或加辰砂。）
消暑降火。散结。通乳滑胎。凡脾虚下陷及精滑者禁之。病有当发表者尤忌。（时珍、士材
俱谓其能发表、 庵亦谓其气轻解肌、不过以其能利毛窍耳、不知表邪得此渗泄重降之品、
必愈陷入里而成败证矣、切勿信以为然。）白而润者良。石苇为使。宜甘草。（走泄之性、宜
甘以和之、嘉言曰∶天水散、取其一甘一寒之意也。阴下湿汗、滑石一两、石膏 半两
、枯白矾五分、研掺之、脚指缝烂、方同上。）
滑石具有通利窍道、行水、体重、泻火的功效。
其味淡，能渗湿；质滑，能利窍；性寒，能泻热。
色白入肺经，能清肃肺气以清除化源，并下行至膀胱以利小便。
它能通利六腑和九窍的津液运行。
它是足太阳膀胱经的本经主药。（膀胱）
主治中暑引起的积热，以及呕吐、心烦、口渴。（注：并非为了止渴而用此药，而是取其通利窍道、渗除湿热的作用，使脾胃气机调和，口渴自然停止。如果没有湿气，且小便通畅却仍口渴者，这是体内有燥热，应当使用滋润之法，如果误服此药，则会进一步耗伤津液，导致口渴更加严重，所以李时珍认为它是极燥烈的药物。）
治疗黄疸、水肿、香港脚（足部肿痛）、淋证及尿闭。（主要侧重治疗石淋。）
治疗水样腹泻、热性痢疾。（若为冷痢，可配伍干姜，用于治疗白痢。）
治疗吐血、鼻衄。
治疗各种疮疡肿毒。
它是荡涤热邪、除湿浊的重要药物。（李时珍说：滑石上能通利皮毛腠理的窍道，是清除中上焦的湿热；下能通利精窍和溺窍，是清除中下焦的湿热。湿热去除后，三焦安宁，表里调和，阑门通畅，阴阳之气得以顺利流通。刘河间的益元散，能治疗表里上下各种疾病，大概就是这个意思。益元散，又名天水散，又名六一散，取“天一生水，地六成之”的含义。方中滑石六钱，甘草一钱，有时加入辰砂。）
具有消暑降火、散结、通乳、滑胎的功效。
凡是脾虚下陷及遗精滑泄者禁用。
疾病需要发汗解表时尤其忌讳使用。（李时珍、沈士材都称它能发表，张庵也认为它气轻能解肌，不过是因为它能通利毛窍罢了。不知道表邪遇到这种渗泄重降的药物，必定会更加陷入体内而变成败证，千万不要相信这是对的。）
白色且润泽的为好。
以石苇为使药。宜与甘草同用。（因其具有走泄之性，宜用甘味药来调和它。喻嘉言说：天水散，取其一甘一寒的意思。对于阴部潮湿多汗，可用滑石一两，石膏半两，枯白矾五分，研成细末外敷。脚趾缝溃烂，方剂同上。）
Hua Shi (Talcum) possesses the functions of unblocking orifices, promoting water metabolism, having a heavy weight, and purging fire.
Its bland nature promotes dampness leaching; its slippery nature facilitates orifice patency; its cold nature clears heat.
Being white, it enters the Lung meridian, clearing the source of transformation and descending to the Bladder to promote urination.
It unblocks the fluid circulation of the Six Fu organs and the Nine Orifices.
It is the principal herb for the Foot-Taiyang (Bladder) meridian. (Bladder)
It treats accumulated heat from summerheat, vomiting, restlessness, and thirst. (Note: It is not used merely to quench thirst, but to unblock orifices and leach out damp-heat, thereby harmonizing the Spleen and Stomach so that thirst ceases naturally. If there is no dampness, yet urination is free and thirst persists, this indicates internal dry-heat, which should be treated with moistening methods. Misuse of this herb will further deplete body fluids, worsening thirst; thus, Li Shizhen considered it an extremely drying agent.)
It treats jaundice, edema, Hong Kong foot (podagra/foot swelling), strangury, and urinary retention. (Primarily indicated for lithiasis/stone strangury.)
It treats watery diarrhea and dysentery with heat. (For cold dysentery, it may be combined with Gan Jiang/Dried Ginger to treat white dysentery.)
It treats hematemesis and epistaxis.
It treats various sores, ulcers, and toxic swellings.
It is a crucial herb for sweeping away heat and eliminating dampness. (Li Shizhen stated: Hua Shi unblocks the orifices of the skin and interstices above, thereby clearing damp-heat in the Upper and Middle Jiao; it unblocks the orifices of semen and urine below, thereby clearing damp-heat in the Middle and Lower Jiao. Once damp-heat is removed, the Three Jiao become tranquil, the interior and exterior harmonize, the Lanmen (gate between small and large intestines) opens, and Yin and Yang flow smoothly. Liu Hejian's Yi Yuan San can treat various diseases of the interior, exterior, upper, and lower levels, based on this principle. Yi Yuan San, also known as Tian Shui San or Liu Yi San, takes its name from the theory "Heaven generates Water One, Earth completes it Six." The formula consists of 6 qian of Hua Shi and 1 qian of Gan Cao, sometimes added with Chen Sha/Cinnabar.)
It has the effects of dissipating summerheat, descending fire, resolving nodules, promoting lactation, and facilitating childbirth.
It is contraindicated in cases of Spleen Qi sinking and seminal emission/spermatorrhea.
It is especially taboo when the disease requires diaphoresis (sweating to release the exterior). (Li Shizhen and Shen Shicai both claimed it could release the exterior, and Zhang An believed its light qi could resolve the muscle layer, merely because it unblocks hair follicles. However, they failed to realize that when exterior pathogens encounter such draining and heavy-descending herbs, they are likely to sink deeper into the interior, leading to critical conditions. Do not believe this to be true.)
The white and moist variety is superior.
Shi Wei (Leaves of Pyrrhosia) serves as an assistant herb. It is best combined with Gan Cao. (Due to its draining and dispersing nature, it should be harmonized with sweet herbs. Yu Jiayan stated: Tian Shui San embodies the principle of one sweet and one cold herb. For dampness and sweating in the genital area, use 1 liang of Hua Shi, 0.5 liang of Shi Gypsum, and 5 fen of Ku Bai Fan/Stewed White Alum, ground into powder for external application. For maceration between toes, the same formula applies.)