大黄四两（酒洗） 芒硝三合 枳实五枚 浓朴半斤
先煎朴、实，将熟内大黄，煮二、三沸，倾碗内和芒硝服。
攻下之法，原因实症俱备，危在旦夕，失此不下，不可复救。故用斩关夺门之法，定难
于俄顷之间，仲景所以有急下存阴之训也。乃后人不明此义，有谓于攻下药中，兼行生津润
导之法，则存阴之力更强，殊不知一用生津滋润之药，则互相牵制，而荡涤之力轻矣！此譬
如寇盗当前，恣其焚掠，所过为墟，一旦聚而歼之，然后人得安居，而元气可以渐复。是去
实可以保阴，乃相因之理，方得“存”字真解。并非谓攻实即是补阴，并可于攻下中寓养阴
法也。仲景制大承气汤，用枳实开上焦，用浓朴通中焦，芒硝理下焦，而以大黄之善走者统
率之，以荡涤三焦之坚实，正聚寇尽歼之大法。而又恐药力太猛，非可轻投，故又有欲用大
承气，先与小承气之训。夫以仲景之神灵，岂尚待于先试，实恐后人审症未确，借口成法，
孟浪轻投，不得不谆谆告诫，此实慎重民命之婆心也。至于三阴多可下之症，三阳惟正阳明
可下，少阳必不可下，而阳明中夹有太阳、少阳症者，亦断不可下。惟太阳症脉紧、恶寒、
无汗、腹痛者，乃阴气凝结营分，亦可用温、用下。细看方书，宜下忌下之条，慎重斟酌，
始为得之。
先煎煮厚朴和枳实，待药液将熟时加入大黄，煮沸二至三次后，倒入碗中，调入芒硝服用。
使用攻下法，是因为实证症状全部具备，病情危急，就在旦夕之间，如果错过这个时机不进行攻下治疗，就无法再挽救了。所以采用像斩关夺门一样的猛烈方法，在极短的时间内平定危难，这就是张仲景所说的“急下存阴”的教诲。然而后人不明白这个道理，有人认为在攻下药中，兼用生津润导的方法，那么保存阴液的力量会更强，却不知道一旦使用了生津滋润的药物，就会互相牵制，导致荡涤邪气的力量变弱！这就像强盗就在眼前，肆意焚烧掠夺，所到之处化为废墟，一旦聚集兵力将其歼灭，然后百姓才能安居，元气才可以逐渐恢复。去除实邪就可以保护阴液，这是相互依存的道理，这才得到了“存”字的真正解释。并不是说攻逐实邪就是补益阴液，也不是说可以在攻下的方剂中寓含养阴的方法。张仲景制定大承气汤，用枳实开通上焦，用厚朴疏通中焦，用芒硝调理下焦，而由善于走窜的大黄统率它们，以荡涤三焦的坚实之邪，这正是聚歼所有寇贼的大法。但又担心药力太猛，不可以轻易投用，所以又有想要使用大承气汤，先给予小承气汤试探的教诲。凭借张仲景的神妙医术，难道还需要先进行试探吗？实在是担心后人辨证不确切，借口成法，鲁莽轻率地用药，不得不谆谆告诫，这确实是爱护百姓生命的慈悲之心啊。至于三阴经多属于可以攻下的证候，三阳经只有正阳明病可以攻下，少阳病绝对不可以攻下，而阳明病中夹杂有太阳、少阳证候的，也绝对不可以攻下。只有太阳病出现脉紧、恶寒、无汗、腹痛的症状，这是阴气凝结在营分，也可以使用温法或下法。仔细研读方书，对于宜下和忌下的条文，慎重斟酌，这才是正确的做法。
Rhubarb (Da Huang) four liang (washed with wine), Niter (Mang Xiao) three he, Immature Bitter Orange (Zhi Shi) five pieces, Magnolia Bark (Hou Po) half jin.
First decoct the Magnolia Bark and Immature Bitter Orange; when nearly ready, add Rhubarb, boil for two or three boils, pour into a bowl, and mix with Niter before taking.
The method of purgation is employed because all signs of excess syndrome are present, and the condition is critical, hanging in the balance. If this opportunity to purge is missed, it cannot be saved again. Therefore, a method akin to "cutting through the gate and seizing the door" is used to stabilize the crisis within an instant. This is why Zhang Zhongjing issued the instruction of "urgent purgation to preserve Yin." However, later generations did not understand this principle. Some claimed that combining methods of generating fluids and moistening guiding within purgative formulas would strengthen the power to preserve Yin. Little do they know that once fluid-generating and moistening herbs are used, they will mutually constrain each other, thereby weakening the power to scour and cleanse! This is like bandits currently at hand, freely burning and looting, leaving ruins wherever they pass. Once gathered and annihilated, then people can live in peace, and the Yuan Qi (Primary Qi) can gradually recover. Removing excess can protect Yin; this is the principle of mutual dependence, which truly interprets the character "preserve" (Cun). It does not mean that attacking excess is equivalent to tonifying Yin, nor does it imply that nourishing Yin methods should be embedded within purgation. Zhang Zhongjing formulated Da Cheng Qi Tang (Major Order the Qi Decoction), using Immature Bitter Orange to open the Upper Jiao, Magnolia Bark to unblock the Middle Jiao, and Niter to regulate the Lower Jiao, while commanding them with Rhubarb, which is good at moving freely, to scour and cleanse the solid excess of the Three Jiaos. This is precisely the great method of annihilating all bandits. Furthermore, fearing that the medicinal force might be too fierce to be administered lightly, there is also the instruction: if one wishes to use Da Cheng Qi Tang, first administer Xiao Cheng Qi Tang (Minor Order the Qi Decoction). Given Zhang Zhongjing's divine efficacy, did he really need to test first? It was actually out of fear that later generations might not diagnose accurately, using established formulas as an excuse to recklessly and lightly administer drugs. Thus, earnest warnings were necessary; this is indeed the compassionate heart of caring for people's lives. As for the Three Yin channels, many conditions are suitable for purgation; among the Three Yang channels, only proper Yangming disease is suitable for purgation, and Shaoyang disease must absolutely not be purged. Moreover, Yangming disease complicated by Taiyang or Shaoyang symptoms must absolutely not be purged. Only when Taiyang disease presents with a tight pulse, aversion to cold, absence of sweating, and abdominal pain—indicating Yin qi congealing in the Ying (Nutrient) level—can warming or purging methods be used. Carefully reviewing formula books, one should cautiously deliberate on the clauses regarding when purgation is indicated and when it is contraindicated; only then is the correct approach achieved.