治大结胸证。脉沉而紧。心下痛按之石硬者。
大黄（六两） 芒硝（一升） 甘遂（一钱匕）
上三味。以水六升。先煮大黄。取二升。去滓。内芒硝。煮一两沸。内甘遂末。温服一
升。
歌曰 一钱甘遂一升硝六两大黄力颇饶。日晡热潮腹痛满。胸前结聚此方消。
蔚按。大黄、芒硝。苦咸之品。借甘遂之毒。直达胸间之饮邪。不专荡胃中之邪秽也。
汤与
味之过而
以遮上下也。膈能拒邪。则邪但留于胸中。膈不能拒邪。则邪留胸而及于胃。胸胃俱病。乃
成结胸。如胸有邪而胃未受邪。则为胸胁满之半表半里证。如胃受邪而胸不留。则为胃家实
之阳明病。皆非结胸也。故必详辨分明。庶无差误。
治小结胸病。正在心下。按之则痛。脉浮滑者主之。又治心下结痛。气喘闷者。
黄连（一两） 半夏（半升 洗。） 栝蒌实（大者一枚）
上三味。以水六升。先煮栝蒌。取三升。去滓。内诸药。煎取二升。去滓。分温三服。
歌曰 按而始痛病犹轻。（与手不可近大结胸证迥别。）脉络凝邪心下成。（曰正在心下。
上
张令韶曰。气分无形之邪结于胸膈之间。以无形而化有形。故痛不可按而为大结胸证。
结于
方
脉络之结热从下而降也。若大结胸证亦用此汤。药不及病。多死。又曰。气无形者也。经。
有形者也。以无形之邪结于胸膈之内。故用大黄、甘遂辈从有形之肠胃而解。结于脉络之间。
又用黄连、半夏辈从无形之气分而散。此经气互相贯通之理。
徐灵胎曰。大承气所下者燥屎。大陷胸所下者蓄水。此所下者为黄涎。涎者轻于蓄水而
未成水者也。审证之精。用药之切如此。
治疗大结胸证。脉象沉而紧，心窝部疼痛，按压时感觉像石头一样坚硬。
以上三味药，用水六升，先煮大黄，取药液二升，滤去药渣，加入芒硝，煮沸一两滚，再加入甘遂末，温服一升。
歌诀云：一钱甘遂、一升芒硝、六两大黄，药力颇为雄厚。日晡时分（下午3-5点）出现潮热，腹部胀满疼痛，胸前积聚之邪气由此方消除。
蔚按（陈念祖自注）：大黄、芒硝属于苦咸性质的药物，借助甘遂的毒性，直达胸膈间的饮邪，并不专门荡涤胃中的秽浊之物。
汤剂的作用在于遮盖上下。膈膜能够抗拒邪气，则邪气只停留在胸中；如果膈膜不能抗拒邪气，则邪气停留于胸并波及到胃。胸和胃都受病，才形成结胸证。如果胸中有邪气而胃未受邪，则表现为胸胁胀满的半表半里证（少阳病）。如果胃受邪气而胸中不留邪，则表现为胃家实（阳明腑实证）。这些都不是结胸证。所以必须详细辨别清楚，才不会出差错。
治疗小结胸病，病位正在心窝部，按压时才疼痛，脉象浮滑者，以此方主治。又用于治疗心窝部结聚疼痛、气喘胸闷者。
以上三味药，用水六升，先煮栝蒌，取药液三升，滤去药渣，加入其他药物，煎取二升，滤去药渣，分三次温服。
歌诀云：只有按压时才疼痛，说明病情较轻。（这与手不可触碰的大结胸证截然不同。）脉络凝滞邪气，在心下结成病块。（文中说“正在心下”。）
张令韶（张隐庵）说：气分中无形的邪气结聚在胸膈之间，因为无形而转化为有形，所以疼痛剧烈且不可按压，从而形成大结胸证。邪气结聚在脉络之间，导致结热从下而降。如果是大结胸证也使用此方（小陷胸汤），药力达不到病所，会导致死亡。又说：气是无形的，经络是有形的。用无形的邪气结聚在胸膈之内，所以使用大黄、甘遂这类药物，通过有形的肠胃来解除邪气。邪气结聚在脉络之间，又使用黄连、半夏这类药物，从无形的气分来消散邪气。这是经气互相贯通的道理。
徐灵胎说：大承气汤所攻下的是燥屎，大陷胸汤所攻下的是蓄水，此方（小陷胸汤）所攻下的是黄涎。涎比蓄水轻，是尚未形成水饮的状态。辨证如此精细，用药如此贴切。
Treats the syndrome of Major Chest Binding (Da Jie Xiong Zheng). The pulse is deep and tight. There is pain in the epigastrium, and palpation reveals hardness like a stone.
Rhubarb Root (Da Huang) - 6 liang
Mirabilite (Mang Xiao) - 1 sheng
Kansui Root (Gan Sui) - 1 qian bi
Take the above three herbs. Add six sheng of water. First decoct Rhubarb Root until two sheng remain. Strain to remove the dregs. Add Mirabilite. Boil for one or two boils. Add Kansui Root powder. Take one sheng warm.
Song says: One qian bi of Kansui Root, one sheng of Mirabilite, six liang of Rhubarb Root; the medicinal power is quite ample. For tidal fever occurring at dusk (ri bu), abdominal fullness and pain, this formula eliminates the accumulation in the chest.
Wei An (Chen Nianzu's commentary): Rhubarb Root and Mirabilite are bitter and salty substances. Relying on the toxicity of Kansui Root, they reach directly to the fluid retention (yin xie) in the chest. They do not specifically purge the filth in the stomach.
The action of the decoction covers both upper and lower regions. If the diaphragm can resist the pathogen, the pathogen remains only in the chest. If the diaphragm cannot resist the pathogen, the pathogen stays in the chest and spreads to the stomach. When both the chest and stomach are diseased, it becomes Chest Binding. If there is pathogen in the chest but the stomach is not affected, it presents as half-exterior half-interior syndrome with chest and hypochondriac fullness (Shaoyang disease). If the stomach is affected but the chest does not retain the pathogen, it presents as Yangming disease with excess in the stomach (Yangming Fu Syndrome). None of these are Chest Binding. Therefore, differentiation must be clear to avoid errors.
Treats Minor Chest Binding (Xiao Jie Xiong Bing). The location is precisely in the epigastrium. Pain occurs only upon palpation. A floating and slippery pulse indicates this formula is indicated. It also treats binding pain in the epigastrium accompanied by asthma and chest oppression.
Coptis Rhizome (Huang Lian) - 1 liang
Pinellia Tuber (Ban Xia) - half sheng (washed)
Trichosanthes Fruit (Gua Lou Shi) - one large fruit
Take the above three herbs. Add six sheng of water. First decoct Trichosanthes Fruit until three sheng remain. Strain to remove the dregs. Add the other herbs. Decoct until two sheng remain. Strain to remove the dregs. Divide into three warm doses.
Song says: Pain only upon palpation indicates the disease is lighter. (This is distinctly different from Major Chest Binding where touch is intolerable.) Pathogenic factors condense in the meridians and form a knot in the epigastrium. ("Precisely in the epigastrium" is stated.)
Zhang Ling Shao (Zhang Yinan) said: Formless pathogenic qi binds between the chest and diaphragm. Because it is formless, it transforms into something tangible, causing severe pain that cannot be touched, thus forming Major Chest Binding. When bound in the meridians, the accumulated heat descends. If Major Chest Binding were treated with this formula (Minor Chest Binding Formula), the medicinal strength would be insufficient for the disease, often leading to death. Furthermore: Qi is formless, while meridians are tangible. To resolve pathogenic qi bound formlessly within the chest and diaphragm, one uses Tangkuei Root (Da Huang) and Kansui Root (Gan Sui) to expel via the tangible intestines and stomach. To resolve binding in the meridians, one uses Coptis Rhizome (Huang Lian) and Pinellia Tuber (Ban Xia) to dissipate from the formless qi level. This illustrates the principle of mutual penetration between meridians and qi.
Xu Ling Tai said: Da Cheng Qi Tang purges dry feces. Da Xian Xiong Tang purges accumulated water. This formula purges yellow phlegm sputum (huang xian). Sputum is lighter than accumulated water and has not yet formed fluid retention. Such precision in syndrome differentiation and appropriateness in medication is remarkable.