伤寒论评话 第33章 组方精当大承气,急下但只为存阴——阳明腑实证的辨证施治(一)

Discussion of Shanghan Lun:Prescription of Dachengqi Tang,Urgent for Yin Existence—Excess Syndrome of Yangming FU-organ

①大承气汤中大黄为刺激性泻下药,芒硝为容积性泻下药,枳实、厚朴则属于调节性泻下药。大黄中的大黄酸,能够刺激胃肠蠕动幅度增大变快;芒硝中的十水合硫酸钠在肠道形成高渗状态;枳实、厚朴对肠道的蠕动及排储进行双向性调节。芒硝形成肠道高渗,水分增多,燥屎得到濡润变软;大黄刺激肠道蠕动的速度变快、幅度变大,促进燥屎下排;枳实、厚朴调节肠道蠕动的节律和幅度,诸药配伍,共奏泻下清热的功效,可见其组方的高度科学性和严谨性。②临床运用大承气汤,既要掌握其使用的指征、还要掌握其使用的时间节点、并需掌握其使用的火候,使用指征如"初头硬,后必溏,不可攻之",必待"屎定硬,乃可攻之";时间节点如"须下者,过经乃可下之;下之若早,语言必乱";攻下的火候如"若一服利,则止后服",就是要做到适合、适时、适度、适当。③急下证从症状看,急下指征并不完全具备,其实是提示既病防变。发热耗津,汗多伤津,其结果必定是津亏热结,燥实阻滞,所以需要早治;发汗病不解,已经损伤了阴津,兼有腹满痛,极有可能是津伤热结,燥屎已成,所以也需要早治,这两条的"急下之"是防止出现阴津耗竭的后果,临床需结合其他症状,籍宜确定是否需要急下。

（1）Dachengqi Tang, Dahuang for irritant cathartic, Mangxiao for volume purgatives, Zhishi and Houpu belong to regulatory purgatives. The rhein in Dahuang can stimulate gastrointestinal motility. Ten hydration of sodium sulfate in Mangxiao can form high permeability. Zhishi and Houpu have bidirectional adjustment for intestinal peristalsis and excretion. Moisture content increase makes dry excrement get moist lip soft. Dahuang stimulates the intestinal peristalsis for faster and larger amplitude and promotes dry excrement discharge. All the medicine compatibility play in the effect of heat with highly scientific and rigorous. （2）The clinical use of Dachengqi Tang,should not only master the use of indications ,but also master the time node and master the timing in cooking. （3）From the symptom of emergencies, the indications are not fully equipped. It is actually prevention before disease. Heat consumption and body fluid consumption lead to the result of accumulation of heat and dry solid block. So it needs to be treated early. That prevents the result of body fluid drain. It should be combined with other clinical symptoms to determine whether the urgent need.