大黄（四两酒洗） 浓朴（半斤炙去皮） 枳实（五枚炙） 芒硝（三两）
上四味。以水一斗。先煮二物取五升。去滓。纳大黄。煮取二升。去滓。纳芒硝。更上
微火一二沸。分温再服。得下。余勿服。
大承气开阳明之结。直达下焦。其力猛而效速。故曰大。盖胃大实。故重任浓朴以破结
。而
数独倍于大黄。矢已硬。故虽有枳实以导下。而功必资于芒硝。至其煎法。尤有深义。浓朴
枳实之汁。以浓而力锐。大黄芒硝之性。以生而力锐。故分作三次煎。此斩关夺门之将。用
此以急下存阴也。
大承气治阳明胃实之主药。必审明表证尽罢。不恶寒。但恶热。或潮热汗出谵语。腹满
痛。
或喘冒不能卧。口干燥。脉滑而实。或涩者。方可用之。下不宜早。早则阳陷。并不宜迟。
迟则阴亡。恰好在阳明胃实之界。一下夺而诸病尽解。临证时不可错过。
阳明居中土。万物所归。无所复传。大热入胃。惟有下夺一法。盖阳明胃实之证。有从
太阳
传入者。有从少阳转属者。并有从三阴转属者。三阴经中。少阴更有急下之证。此乃伤寒一
大归宿。若应下失下。变证蜂起。津液之亡。可立而待。孟浪不可。因循亦不可。
大承气证非惟不大便腹满痛者宜之。即下利之证。亦有宜从下夺者。如经文所指下利不
欲食
。下利心下硬。下利脉反滑。下利脉迟而滑。少阴病自利清水色纯青。心下痛。口干燥者。
皆宜大承气。此通因通用之法。不可不知。
大黄（四两，用酒清洗） 浓朴（半斤，炙烤后去皮） 枳实（五枚，炙烤） 芒硝（三两）
以上四味药。用水一斗。先煮浓朴和枳实两味药，取汁液五升。滤去药渣。加入大黄。继续煎煮，取汁液二升。滤去药渣。加入芒硝。再放在微火上煮一二沸。分两次温服。如果大便通下。剩下的药液不要服用。
大承气汤能开通阳明经的结滞。药力直达下焦。它的药力猛烈而见效迅速。所以称为“大”。因为胃中实热严重，所以重用浓朴来破除结滞。而且浓朴的用量是大黄的两倍。大便已经干硬，所以虽然有枳实来引导下行，但功效必须依靠芒硝。至于它的煎煮方法，尤其有深意。浓朴和枳实的汁液，因为浓度高而药力锐利；大黄和芒硝的药性，因为生用而药力锐利。所以分三次煎煮。这是像斩关夺门一样的猛将，使用这种方法来急下以保存阴液。
大承气汤是治疗阳明胃实证的主药。必须审察清楚表证已经完全解除，不恶寒，只恶热，或者潮热、出汗、说胡话，腹部胀满疼痛。或者气喘、头昏不能躺卧，口干燥。脉象滑而实，或者涩。才可以服用它。攻下不宜过早，过早则阳气下陷。也不宜过迟，过迟则阴液亡失。恰好在阳明胃实证的界限上，一下夺邪气而各种病症全部解除。临证时不可错过。
阳明经居中属土，是万物归聚之处，病邪不再传变。大热进入胃中，只有攻下一法。大概阳明胃实证的病证，有从太阳经传入的，有从少阳经转属的，并有从三阴经转属的。在三阴经中，少阴经更有急下的证候。这是伤寒的一大归宿。如果应当攻下却失去攻下的时机，变证蜂拥而起。津液的亡失，可以立刻等待到（即很快发生）。轻率鲁莽不可以，因循守旧也不可以。
大承气汤的证候，不仅仅是大便不通、腹部胀满疼痛者适宜使用。即使是下利的证候，也有适宜从攻下夺邪的。如经文所指的下利不想吃东西，下利心下部坚硬，下利脉象反而滑，下利脉象迟而滑，少阴病自利清水颜色纯青，心下部疼痛，口干燥的。都适宜用大承气汤。这是通因通用的治疗方法，不可不知道。
Rhubarb (4 liang, washed with wine) Zanthoxyli Pericarpium (8 liang, roasted and skin removed) Immature Bitter Orange (5 pieces, roasted) Mirabilite (3 liang)
The above four ingredients. Use one dou of water. First decoct Zanthoxyli Pericarpium and Immature Bitter Orange to obtain five sheng of liquid. Remove the dregs. Add Rhubarb. Decoct to obtain two sheng of liquid. Remove the dregs. Add Mirabilite. Heat gently on a low fire for one or two boils. Divide into two doses and take warm. If bowel movement occurs, do not consume the remaining medicine.
Da Cheng Qi Tang opens the stagnation of Yangming channel. Its effect reaches directly to the lower jiao. Its power is fierce and its efficacy is rapid. Hence it is called "Da" (Great). Because the stomach has severe excess heat, Zanthoxyli Pericarpium is heavily used to break the stagnation. Moreover, the dosage of Zanthoxyli Pericarpium is double that of Rhubarb. Since the stool is already hard, although Immature Bitter Orange guides downward, the efficacy must rely on Mirabilite. Regarding its decoction method, there is particularly profound meaning. The juices of Zanthoxyli Pericarpium and Immature Bitter Orange are concentrated and potent; the properties of Rhubarb and Mirabilite are sharp because they are used raw. Therefore, they are decocted in three stages. This is like a general who breaches gates and captures doors; this method is used to urgently purge to preserve Yin fluid.
Da Cheng Qi Tang is the principal formula for treating Yangming Stomach Excess syndrome. One must carefully ascertain that exterior syndromes have completely resolved, without aversion to cold, but only aversion to heat, or tidal fever, sweating, delirious speech, abdominal fullness and pain. Or wheezing, dizziness, inability to lie down, dry mouth. Pulse is slippery and excess, or choppy. Only then can it be used. Purging should not be done too early; doing so causes Yang to sink. Nor should it be delayed; delaying causes Yin to perish. It is precisely at the boundary of Yangming Stomach Excess syndrome; once purged, all diseases resolve. In clinical practice, one must not miss this opportunity.
Yangming resides in the center, belonging to Earth, where all things return, and no further transmission occurs. When great heat enters the stomach, there is only the method of purging. Generally, Yangming Stomach Excess syndromes may transmit from Taiyang channel, transfer from Shaoyang channel, or transfer from the Three Yin channels. Among the Three Yin channels, Shaoyin channel also has urgent purging syndromes. This is a major destination of Shanghan (Cold Damage). If purging is indicated but missed, variable syndromes will arise like swarms. The loss of Jin-Ye (body fluids) can be expected immediately. Recklessness is inadvisable, as is procrastination.
Da Cheng Qi Tang syndrome is suitable not only for those with constipation, abdominal fullness, and pain. Even in cases of diarrhea, purging may be appropriate. As stated in the classic text: diarrhea with lack of appetite, diarrhea with hardness in the epigastrium, diarrhea with a surprisingly slippery pulse, diarrhea with a slow and slippery pulse, Shaoyin disease with spontaneous discharge of clear green water, pain in the epigastrium, and dry mouth. All these are suitable for Da Cheng Qi Tang. This is the method of "treating obstruction with unblocking agents" (Tong Yin Yong Tong), which must be known.