气寒，味苦辛。
《象》云∶除寒热邪气，逐六腑积聚，结痼留癖，胃中食饮热结。去血闭，停痰痞满。
消毒。揉细，生用。
即芒硝
气寒，味咸。
《心》云∶去实热。《经》云∶热淫于内，治以咸寒，此之谓也。
《珍》云∶纯阴，热淫于内，治以咸寒。
《本草》云∶主五脏积聚，久热胃闭。除邪气，破留血，腹中痰实结搏。通经脉及月水
，破五淋。消肿毒，疗天行热病。
《药性论》云∶使。味咸。有小毒。通月闭症瘕，下瘰 ，黄胆，主漆疮，散恶血。
《圣惠方》云∶治代指用芒硝煎汤，淋渍之，愈。
气寒，味甘、辛。一作苦、辛，大寒。无毒。又云∶咸。又云∶甜，甜微缓于咸。
《液》云∶硝石者硝之总名也。但不经火者谓之生硝、朴硝，经火者谓之盆硝、芒
硝。古人用辛，今人用咸。辛能润燥，咸能软坚，其意皆是，老弱虚人可下者宜用。若用此
者，以玄明粉代之尤佳。《本经》谓利小便而堕胎，伤寒妊娠可下者用此，兼以大黄引之
，直入大肠，润燥、软坚、泻热，子母俱安。《内经》云∶有故无殒，亦无殒也。此之谓
欤。以在下言之，则便溺俱阴；以前后言之，则前气后血；以肾言之，总主大小便难。溺涩
秘结，俱为水少。《经》云∶
热淫于内，治以咸寒，佐以苦。故以芒硝、大黄，相须为使也。
【朴硝】
气味：气寒，味苦、辛。
《汤液本草·象》记载：能清除寒热邪气，驱逐六腑中的积聚之物，消除顽固的结块和癖积，以及胃中因饮食积滞产生的热结。能去除血闭不通，消除停聚的痰饮导致的痞满症状。
具有消毒作用。使用时需揉碎，生用。
【芒硝】
即芒硝。
气味：气寒，味咸。
《汤液本草·心》记载：能去除实热。《汤液本草·经》记载：体内热邪炽盛时，应用咸寒之品治疗，说的就是这种情况。
《汤液本草·珍》记载：芒硝属纯阴之品，体内热邪炽盛时，应用咸寒之品治疗。
《汤液本草·本草》记载：主治五脏积聚，久热导致的胃气闭塞。能排除邪气，破除留滞的血瘀，治疗腹中痰湿与实邪结聚搏结。能通调经脉及月经，破除五种淋证（石淋、血淋、膏淋、劳淋、热淋）。能消肿毒，治疗流行性热病。
《药性论》记载：作为使药使用。味咸。有小毒。能通调月经闭止及癥瘕积聚，排出瘰疬，治疗黄疸，主治漆疮，消散恶血。
《圣惠方》记载：治疗代指（指甲周围红肿疼痛）时，用芒硝煎汤，淋洗浸泡患处，即可痊愈。
【硝石】
气味：气寒，味甘、辛。另一种说法是味苦、辛，大寒。无毒。又有说法认为是咸味。还有说法认为其味甜，甜味比咸味稍缓。
《汤液本草·液》记载：硝石是硝类的总称。但未经火炼的称为生硝、朴硝，经过火炼的称为盆硝、芒硝。古人多用其辛味，今人多用其咸味。辛味能润燥，咸味能软坚散结，两者的用意都是正确的。对于年老体弱或虚损之人，若需用下法攻逐，宜选用此药。如果使用此类药物，用玄明粉替代尤为适宜。《神农本草经》记载其能利小便并导致堕胎，但在伤寒病且妊娠期间确需攻下的情况下可以使用，配合大黄引导药力，直入大肠，起到润燥、软坚、泻热的作用，从而使母子平安。《黄帝内经》说：“有病则病受之，故无损伤”，说的就是这个道理。从位置在下而言，大小便均属阴；从前阴后阴而言，前主气后主血；从肾脏而言，主要主管大小便困难。尿涩便秘，都是因为津液不足所致。《黄帝内经》说：“体内热邪炽盛，用咸寒之法治疗，辅以苦味。”因此，芒硝与大黄相互为用，相辅相成。
[Puo Xiao]
Nature and Flavor: Cold in nature, bitter and acrid in flavor.
*Xiang* states: It eliminates pathogenic factors of cold and heat, expels accumulations in the six fu organs, resolves stubborn masses and fixed stasis, and clears heat accumulation from food and drink in the stomach. It removes blood obstruction and stagnation of phlegm causing fullness and oppression.
It has detoxifying effects. It should be rubbed into fine powder and used raw.
[Mang Xiao]
Also known as Mang Xiao (Sodium Sulfate).
Nature and Flavor: Cold in nature, salty in flavor.
*Xin* states: It eliminates excess heat. *Jing* states: When excessive heat invades internally, it is treated with salty-cold substances; this refers to such cases.
*Zhen* states: It is purely yin. When excessive heat invades internally, it is treated with salty-cold substances.
*Benzao* states: It governs accumulations in the five zang organs, chronic heat causing closure of the stomach. It eliminates pathogenic factors, breaks up retained blood, and treats phlegm-dampness and solid matter knotting in the abdomen. It unblocks the meridians and menstruation, and breaks up the five types of strangury (Lin syndrome). It reduces swelling and toxicity, and treats epidemic febrile diseases.
*Yaoxing Lun* states: It serves as an envoy herb. Salty in flavor. Slightly toxic. It unblocks menstrual amenorrhea and zheng-jia masses, drains scrofula, jaundice, governs lacquer dermatitis, and disperses evil blood.
*Shenghui Fang* states: To treat daizhi (paronychia/infection around the nail), boil Mang Xiao in water, and wash/soak the affected area until healed.
[Xiao Shi]
Nature and Flavor: Cold in nature, sweet and acrid in flavor. Another version says bitter and acrid, greatly cold. Non-toxic. Yet another view holds it is salty. Some say it tastes sweet, with sweetness being slightly milder than saltiness.
*Ye* states: Xiao Shi is the general name for all nitrates/salts. Those not processed by fire are called Sheng Xiao or Pu Xiao; those processed by fire are called Pen Xiao or Mang Xiao. Ancients utilized its acrid quality, while modern practitioners utilize its salty quality. Acridity can moisten dryness, while saltiness can soften hardness; both intentions are valid. For the elderly, weak, or deficient individuals requiring purgation, this substance is suitable. If using such substances, substituting with Xuan Ming Fen (Refined Sodium Sulfate) is particularly excellent. *Ben Jing* states it promotes urination and causes abortion. However, in cases of Shanghan (Cold Damage) where purgation is indicated during pregnancy, it may be used, guided by Dahuang (Rhubarb Root) to enter the large intestine directly, moistening dryness, softening hardness, and purging heat, thereby ensuring safety for both mother and child. *Neijing* states: "If there is a disease, there will be no injury [to the healthy qi], nor will there be injury [to the fetus]." This is what is meant. Speaking from the perspective of the lower body, urine and stool are both yin; speaking from the front and back orifices, the front governs qi and the rear governs blood; speaking from the Kidney, it generally governs difficulty in urination and defecation. Urinary retention and constipation are both due to insufficient fluids. *Jing* states: "When excessive heat invades internally, treat with salty-cold methods, assisted by bitter." Therefore, Mang Xiao and Dahuang act as mutual assistants.