【气味】苦，大寒，无毒。时珍曰∶辛、苦，大温，无毒。
【主治】风热癫痫，小儿惊邪螈 ，风眩头痛，肺壅耳聋，口疮喉痹咽塞，牙颔肿痛，
目赤热痛，多眵泪（《开宝》）。
【发明】土宿真君曰∶硝石，感海卤之气所产，乃天地至神之物，能寒能热，能滑能涩，
能辛能苦，能酸能咸，入地千年，其色不变，七十二石，化而为水，制服草木，柔润五金，
制炼八石，虽大丹亦不舍此也。
时珍曰∶土宿所说，乃硝石神化之妙。《别录》列于朴硝之下，误矣。朴硝属水，味咸
而气寒，其性下走，不能上升，阴中之阴也。故惟荡涤肠胃积滞，折治三焦邪火。硝石属火，
味辛带苦微咸，而气大温，其性上升，水中之火也。故能破积散坚，治诸热病，升散三焦火
郁，调和脏腑虚寒。与硫黄同用，则配类二气，均调阴阳，有升降水火之功，治冷热缓急之
病。 制礞石，则除积滞痰饮。盖硫黄之性暖而利，其性下行；硝石之性暖而散，其性上行。
礞石之性寒而下，硝石之性暖而上。一升一降，一阴一阳，此制方之妙也。今兵家造烽火铳
机等物，用硝石者，直入云汉，其性升可知矣。《雷公炮炙论》序云∶脑痛欲死，鼻投硝末，
是亦取其上升辛散，乃从治之义。《本经》言其寒，《别录》言其大寒，正与龙脑性寒之误相
似。凡辛苦物未有大寒者，况此物得火则焰生，与樟脑、火酒之性同，安有性寒、大寒之理
哉？《史记·仓公传》云∶ 川王美人怀子不乳，来召淳于意。意往饮以茛菪药一撮，以酒
饮之，旋乳。意复诊其脉躁，躁者有余病，即饮以硝石一剂，出血，血如豆比五六枚而安。
此去血结之验也。
【附方】旧四，新十。
头痛欲死∶硝石末吹鼻内，即愈。（《炮炙论》）
诸心腹痛∶焰硝、雄黄各一钱。研细末。每点少许入 内。名火龙丹。（《集玄方》）
腰腹诸痛∶方同上。
赤眼肿痛∶硝石末，卧时，以铜箸点黍米大入目 。至旦，以盐水洗去之。（《圣惠方》
）
眼目障翳∶男女内外障翳，或三、五个月不见效者，一点复明。好焰硝一两，铜器熔化，
入飞过黄丹二分，片脑二分，铜匙急抄入罐内，收之。每点少许，其效如神。兖州朱秀才忽
不见物，朝夕拜天，因梦神传此方，点之而愈。（《张三丰仙方》）
风热喉痹及缠喉风病。玉钥匙∶用焰硝一两半，白僵蚕一钱，硼砂半两，脑子一字。为
末。吹之。（《三因方》）
重舌鹅口∶竹沥，同焰硝点之。（《普济》）
伏暑泻痢及肠风下血，或酒毒下血，一服见效，远年者不过三服。硝石、舶上硫黄各一
两，白矾、滑石半两，飞面四两，为末，滴水丸梧子大。每新汲水下三、五十丸。名甘露丸。
（《普济方》）
五种淋疾∶劳淋、血淋、热淋、气淋、石淋及小便不通至甚者。透格散∶用硝石一两，
不夹泥土雪白者，生研为末。每服二钱，各依汤使。劳淋，劳倦虚损，小便不出，小腹急痛，
葵子末煎汤下，通后便须服补虚丸散。血淋，小便不出时，下血疼痛满急；热淋，小便热，
赤色，脐下急痛，并用冷水调下。气淋，小腹满急，尿后常有余沥，木通煎汤下。石淋，茎
内痛，尿不能出，内引小腹膨胀急痛，尿下砂石，令人闷绝，将药末先入铫内，隔纸炒至纸
焦为度，再研，用温水调下。小便不通，小麦汤下。猝患诸淋，只以冷水下。并空心，调药
使硝如水，乃服之。（沈存中《灵苑方》）
蛟龙症病∶方见雄黄发明下。
服石发疮疼不可忍∶用纸圈围之，中心填硝石令满，以匙抄水淋之。觉不热痛，即止。
（《兵部手集》）
发背初起∶恶寒啬啬，或已生疮肿瘾疹。硝石三两，暖水一升，泡化，待冷，青布折三
重，湿拓赤处，热即换，频易取瘥。（《外台秘要》）
女劳黑疸∶仲景曰∶黄家日晡发热，反恶寒，此为女劳得之。膀胱急，小腹满，身尽黄
，额上黑，足下热，因作黑疸。腹胀如水，大便黑，时溏，非水也。腹满者难治。硝石、矾
石（烧）等分。为末。以大麦粥汁和服方寸匕，日三。病随大小便去，小便黄，大便黑，是
其候也。（《金匮》）
手足不遂大风，及丹石热风不遂。用硝石一两，生乌麻油二斤。置铛中，以土堑盖口，
纸泥固济，火煎。初时气腥，熟则气香。更以生麻油二升，合煎得所，收不津器中。服时坐
室中，重作小纸屋，燃火于内，服一大合，发汗，力壮者日二服。三七日，头面 疮皆减也，
然必以火为使。（波罗门僧方）
[Scent and Flavor] Bitter, extremely cold, non-toxic. Li Shizhen says: Pungent, bitter, extremely warm, non-toxic.
[Indications] Wind-heat-induced epilepsy (epilepsy caused by wind-heat pathogen), pediatric convulsive disorders (convulsions in children due to fright or wind), wind-dizziness headache, lung qi stagnation causing deafness, mouth ulcers, throat bi (sore throat with obstruction) and pharyngeal blockage, swelling and pain of the gums and jaw, red, hot, and painful eyes, excessive eye discharge and tearing (from *Kaibao Bencao*).
[Elucidation] Tuxu Zhenjun said: Niter is produced by sensing the vapor of sea salt brine; it is a miraculous substance of heaven and earth. It can be cold or warm, slippery or astringent, pungent or bitter, sour or salty. Having remained underground for a thousand years, its color does not change. It can transform seventy-two types of minerals into water, subdue plants, soften metals, refine eight minerals, and even great elixirs cannot do without it.
Li Shizhen said: What Tuxu described is the miraculous transformation of niter. *Bielu* listed it under Mang nitre (Mirabilite), which is an error. Mang nitre belongs to Water, tastes salty and is cold in nature; its action moves downward and cannot ascend, making it Yin within Yin. Thus, it only cleanses accumulation and stagnation in the intestines and stomach, and suppresses evil fire in the San Jiao (Triple Burner). Niter belongs to Fire, tastes pungent with slight bitterness and saltiness, and is extremely warm in nature; its action ascends, representing Fire within Water. Therefore, it can break accumulations, dissipate hardness, treat various heat diseases, ascend and disperse stagnant fire in the San Jiao, and harmonize deficiency-cold in the Zang-Fu organs. When used with Sulfur (Sulfurum), it combines the two Qi, balances Yin and Yang, and has the function of ascending and descending Water and Fire, treating conditions of cold, heat, slackness, and urgency. When processed with Qing Shi (Lapis Micae), it eliminates stagnation and phlegm-fluid retention. Generally, Sulfur is warm and purgative, acting downward; Niter is warm and dispersing, acting upward. Qing Shi is cold and sinking, while Niter is warm and ascending. One ascends, one descends; one is Yin, one is Yang; this is the subtlety of formula preparation. Now, when the military manufactures beacon fires and firearms, using Niter allows them to shoot straight into the clouds, proving its ascending nature. The preface of *Leigong Paozhi Lun* states: "For severe brain pain, insert Niter powder into the nose." This also utilizes its ascending and pungent-dispersing nature, following the principle of contrary treatment. *Benjing* states it is cold, and *Bielu* states it is extremely cold, which resembles the error regarding the cold nature of Borneolum Syntheticum (Ice Borneol). Generally, substances that are pungent and bitter are not extremely cold. Moreover, this substance produces flame when exposed to fire, sharing the nature of Camphora (Camphor) and distilled spirits; how could it be cold or extremely cold? *Shiji · Biography of Cang Gong* records: "The Concubine of King Chuan was pregnant but could not lactate, so she summoned Chunyu Yi. Yi went and gave her a pinch of Henbane medicine (Hyoscyami Semen), taken with wine, after which she immediately lactated. Yi re-examined her pulse, finding it restless. Restlessness indicates excess pathology, so he gave her a dose of Niter. She expelled blood, about five or six pieces the size of beans, and then recovered." This is evidence of removing blood stasis.
[Attached Formulas] Four old formulas, ten new formulas.
Severe Headache: Blowing Niter powder into the nostrils brings immediate relief. (*Paosheng Lun*)
Various Heart and Abdominal Pain: Yan Xiao (Refined Niter) and Realgar (Realgar) each 1 qian. Grind into fine powder. Apply a small amount to the affected area. Named Huolong Dan (Fire Dragon Pill). (*Jixuan Fang*)
Various Waist and Abdominal Pains: Same formula as above.
Red and Swollen Painful Eyes: At bedtime, apply a millet-sized amount of Niter powder into the eye using a chopstick. In the morning, wash it out with salt water. (*Shenghui Fang*)
Eye Opacity/Cataracts: For internal and external opacity in men and women, even if ineffective after three to five months, one application restores vision. Take 1 liang of good Yan Xiao, melt it in a copper vessel, add 2 fen of calcined Minium (Lead Oxide) and 2 fen of Borneolum Syntheticum (Ice Borneol). Quickly scoop into a jar with a copper spoon and store. Apply a small amount per use; the effect is miraculous. Scholar Zhu from Yanzhou suddenly lost his sight, praying to heaven day and night. He dreamed of a deity transmitting this formula, and upon application, he recovered. (*Zhang Sanfeng Xianfang*)
Wind-Heat Throat Bi and Winding Throat Wind Disease. Yu Yaoshi (Jade Key): Use 1.5 liang of Yan Xiao, 1 qian of White Silkworm (Bombyx Batryticatus), 0.5 liang of Borax (Borax), and 1 zi of Borneolum Syntheticum (Ice Borneol). Grind into powder and insufflate into the throat. (*Sanyin Fang*)
Double Tongue and Goose Mouth: Dripping Bamboo Sap mixed with Yan Xiao. (*Puji Fang*)
Summerheat Retention Diarrhea/ Dysentery, Intestinal Wind Bleeding, or Alcohol Toxicity Bleeding: Effective after one dose; chronic cases resolve within three doses. Niter and imported Sulfur each 1 liang, Alum (Alumen) and Talcum (Talcus) 0.5 liang, refined flour 4 liang. Grind into powder, make pills with dripping water the size of wutong seeds. Take 30-50 pills with fresh well water. Named Ganlu Wan (Sweet Dew Pill). (*Puji Fang*)
Five Types of Lin Syndrome: Lao Lin (Exhaustion Lin), Xue Lin (Blood Lin), Re Lin (Heat Lin), Qi Lin (Qi Lin), Shi Lin (Stone Lin), and severe urinary retention. Touge San (Penetrating Obstruction Powder): Use 1 liang of pure white Niter free of soil impurities, raw-ground into powder. Take 2 qian per dose, administered according to specific decoctions for each type.
- Lao Lin: Caused by fatigue and deficiency, inability to urinate, urgent lower abdominal pain. Administer with Okra seed powder decoction. After urination resumes, take tonifying pills/powders.
- Xue Lin: Inability to urinate accompanied by bleeding, pain, and fullness.
- Re Lin: Hot urination, red color, urgent pain below the umbilicus. Both Xue Lin and Re Lin are administered with cold water.
- Qi Lin: Lower abdominal fullness and urgency, dribbling after urination. Administer with Akebia Decoction (Akebiae Caulis).
- Shi Lin: Pain in the urethra, inability to urinate, radiating to lower abdominal distension and urgency, passing sand/stones, causing fainting. First, stir-fry the powder over paper until the paper burns, then regrind. Administer with warm water.
- Urinary Retention: Administer with Wheat Decoction.
- Acute onset of any Lin syndrome: Administer with cold water. Take on an empty stomach, mixing the medicine with water like liquid Niter before ingestion. (Shen Cunzhong, *Lingyuan Fang*)
Jiaolong Mass Disease: See Realgar Elucidation.
Unbearable Pain from Stone-Medication Sores: Surround the area with a paper ring, fill the center completely with Niter, and pour water over it with a spoon. Stop when no heat or pain is felt. (*Bingbu Shouji*)
Early Stage Back Carbuncle: Feeling chilly or developing sores/rashes. Dissolve 3 liang of Niter in 1 sheng of warm water. Let cool. Fold green cloth three times, wet compress the red area. Replace when hot, changing frequently until healed. (*Waitai Miyao*)
Female Labor Black Jaundice: Zhang Zhongjing said: "Jaundice patients fever in the late afternoon, yet feel aversion to cold; this is caused by female labor. Urgency of the bladder, fullness of the lower abdomen, yellowing of the whole body, black forehead, heat in the soles of the feet—thus forming Black Jaundice. Abdominal distension like water, black stool, occasionally loose, not watery diarrhea. Abdominal fullness is difficult to treat. Niter and Calcined Alum in equal parts. Grind into powder. Mix with barley gruel juice and take one fangcun bi (measure) per dose, three times daily. The disease exits via urine and stool; yellow urine and black stool indicate recovery." (*Jingui Yaolue*)
Hemiplegia from Great Wind, and Hemiplegia from Dan-Shi Wind-Heat: Use 1 liang of Niter and 2 jin of raw Sesame Oil. Place in a cauldron, cover with earth, seal with paper mud, and simmer over fire. Initially smelly, becomes fragrant when cooked. Add another 2 sheng of raw sesame oil and continue simmering appropriately. Store in a non-porous container. To take, sit in a room where a small paper hut has been built with fire burning inside. Take one dahe (measure), induce sweating. Those with strong constitutions take twice daily. After 21 days, head and facial sores will diminish. However, fire must be used as an assistant method. (Brahmin Monk Formula)