近来为医，纯用大黄者，当时气流行之际，则延请之人，履满户外，必私嘱从人，以先
到为
幸，何也？夫欲服大黄之名，必壮热如燎，全不思纳；或神昏谵语，势甚危急。医人一到，
若遇神仙。然能用大黄，诚非难事。如伤寒传经，至阳明里证，腹满拒按，面带黑滞，下
出燥粪便愈。至于温疫，必舌黄胸痞，不甚拒按，面色亦带黑滞，所下如胶似漆。其疫邪一
分不尽，则病不瘳。故不妨数下，邪尽则愈。人见如此重症，得一下或数下而痊，声便骤通
，群称妙手。此不过阅历既深，临症毅然不移耳。然终归粗工，为时医则可∶若能于杂症中
用之，方为作手。往时邻家子患大腹与两腿小疮密密，当卧时则作痒，辄夜爬抓，脓血淋漓
；至晨不痒而结痂，及夜仍然。外科治以清解燥湿无效，继用补血散风更甚，年余不痊。后
至旧青浦陈家，曰此疮从脏腑蓄毒所发，须服丸料，半年可愈。方用大黄、犀角，余不尽悉
。服丸渐觉痒减，脓水亦少，半年果痊。更有张姓，平时毫无所患，惟过友戚家，虽门素识
，常误入别舍，而自不觉也。后遇徐君洄溪因述其故，徐曰∶必得雪虾蟆配药，能除此症，
但此物难求，我尚有一枚。修丸与君，张服完，病如失。后问雪虾蟆从何而得，徐曰∶那有
此物，丸中首用大黄，明言恐君不服，故谬言之耳。如二君者，皆能知人所不知，如是始可
尽大黄之用矣。
近来行医，单纯使用大黄的患者，在气机流行通畅的时候，求诊的人挤满了门口，必定私下嘱咐随从，以能第一个见到医生为幸运。为什么呢？因为想要服用大黄的名声（指病情严重到非用大黄不可），必须是大热如火烧，完全不想进食；或者是神志昏迷、胡言乱语，形势非常危急。医生一到，就像遇到了神仙一样。然而能够使用大黄，确实不是难事。比如伤寒病传经至阳明里证，腹部胀满且拒绝按压，面色发黑晦暗，排出干燥粪便后痊愈。至于温疫，一定是舌苔黄、胸膈痞闷，虽然不太拒绝按压，但面色也带有黑滞，排出的大便像胶漆一样黏稠。疫病邪气只要有一分没有清除干净，病就不会好。所以不妨多次攻下，邪气尽除则痊愈。人们看到如此重症，经过一次或几次攻下而痊愈，声音气息立刻通畅，众人称赞是妙手。这不过是阅历深厚，临症时果断坚定不动摇罢了。但这终究属于粗疏的工匠，作为当时的普通医生还可以；如果能在杂症中使用大黄，才算是高明的医生。
过去邻居家的儿子患有大腹病和双腿密密麻麻的小疮，躺下时就发痒，总是夜里抓挠，脓血淋漓；到了早晨就不痒并结痂，到了晚上又恢复原状。外科医生用清热解表、燥湿的方法无效，接着用补血散风的方法反而更严重，一年多没有痊愈。后来去旧青浦陈家，医生说：“这个疮是从脏腑蓄积的毒邪发作出来的，必须服用丸药，半年可以痊愈。”方子用了大黄、犀角，其余的不全知道。服用丸药后渐渐觉得瘙痒减轻，脓水也少了，半年果然痊愈。
还有姓张的人，平时毫无病患，只是去过朋友亲戚家，虽然是熟悉的门路，却经常误入别人的屋子，自己却没有察觉。后来遇到徐洄溪先生，向他述说了这件事。徐先生说：“一定需要用雪虾蟆配药，才能消除这个病症，但这种东西很难求得，我还有一枚。”于是制作丸药给他，张先生服完，病就好了。后来问雪虾蟆是从哪里得来的，徐先生说：“哪有这样的东西，丸药中首要是大黄，明说恐怕你不服从，所以故意骗你的罢了。”像这两位医生，都能做到别人做不到的事情，像这样才可以穷尽大黄的功效了。
In recent times, when physicians treat patients using solely Rhizoma Rhei (Dahuang, 大黄), during periods when the vital energy flows smoothly, seekers of medical help crowd the doorstep. They privately instruct their attendants to hope for being seen first. Why is this? Because the reputation of utilizing Rhizoma Rhei applies to cases where high fever burns like fire, with complete loss of appetite; or where there is coma and delirious speech, in a critical state. When the physician arrives, it is as if a deity has appeared. However, the ability to utilize Rhizoma Rhei is indeed not difficult. For instance, in Cold Damage (Shanghan, 伤寒) transmitting through the meridians to Yangming interior syndrome, characterized by abdominal fullness and tenderness upon pressure, dark and dull complexion, recovery occurs after the passage of dry feces. Regarding Warm Epidemic diseases, symptoms must include yellow tongue coating and chest oppression, with less resistance to pressure, yet the complexion also appears dark and dull, and the stool is sticky like glue or lacquer. As long as even one part of the epidemic pathogen remains uneliminated, the illness will not heal. Therefore, multiple purgations are permissible; once the pathogen is exhausted, the patient recovers. Observers seeing such severe illnesses cured after one or several purgations, with immediate restoration of voice and breath, praise the doctor as a miraculous hand. This is merely the result of profound experience and firm resolve in clinical practice. Nevertheless, this ultimately belongs to the work of a crude artisan; suitable for a contemporary general practitioner, but true mastery is demonstrated only when Rhizoma Rhei is employed in miscellaneous diseases.
Previously, the son of a neighbor suffered from an enlarged abdomen and numerous small sores densely covering both legs. The itching intensified when lying down, leading to nocturnal scratching with oozing pus and blood; by morning, the itching ceased and scabs formed, only to recur at night. Surgical treatments employing clearing heat, resolving toxicity, and drying dampness were ineffective. Subsequent use of formulas for nourishing blood and dispersing wind exacerbated the condition, which persisted for over a year. Later, visiting the Chen family in old Qingpu, the physician stated: "This sore arises from toxic accumulation within the zang-fu organs. It requires taking pill medicine, and recovery can be expected in half a year." The formula utilized Rhizoma Rhei (Dahuang, 大黄) and Cornu Rinocerontis (Xijiao, 犀角); the remaining ingredients were unknown. Upon taking the pills, the itching gradually decreased, and the discharge diminished. Indeed, he recovered after six months.
There was also a Mr. Zhang who had no prior ailments, except that when visiting friends or relatives, despite familiar paths, he often mistakenly entered other households without realizing it. Later, encountering Dr. Xu Huixi, he recounted this issue. Dr. Xu said: "It must be treated with a prescription containing Snow Toad (Xuexia, 雪虾蟆) to eliminate this symptom, but this substance is hard to obtain. I possess one specimen." He prepared pills for him. After Mr. Zhang finished the course, the ailment vanished. Later asked where the Snow Toad came from, Dr. Xu replied: "Where would such a thing come from? The primary ingredient in the pills is Rhizoma Rhei (Dahuang, 大黄). I explicitly mentioned it fearing you might refuse, so I fabricated the story." Physicians like these two, who can achieve what others cannot, are truly capable of fully exploiting the utility of Rhizoma Rhei.