尝读仲景书。至金匮要略第三论。乃以阴阳二毒之症。附于百合狐惑目赤黑之尾。反复
玩之。而知斯五症。皆奇症也。百合之状。欲食不食。欲卧不卧。欲行不行。如寒无寒。如热无
热。状如神灵。何其奇也。狐惑之状。嘿嘿欲眠。目不得瞑。蚀喉为惑。蚀阴为狐。面目乍赤
。乍黑。乍白。又何其奇也。目赤黑之状。不热而烦。嘿嘿欲卧。三四日目赤。七八日 黑
。又何其奇也。阳毒则面赤如锦。咽痛吐血。阴毒则面目俱青。咽痛。身如被杖。俱以五日
可治。七日不可治。及其施治。则二症均用升麻鳖甲汤。则不可解已。在阳毒之热。反加
蜀椒。在阴毒之寒。反去蜀椒。则更不可解矣。味其叙阳毒。不过曰面赤咽疼。唾脓血而已
。并不言亢阳极热之状也。其叙阴毒。不过曰面青咽痛。身如被杖而已。并不言至阴极寒之状
也。其所用剂。不过升麻甘草。鳖甲当归而已。并不用大寒大热之药
也。乃知仲景所谓阳毒者。感天地恶毒之异气入于阳经。则为阳毒。入于阴经。则为阴毒。
故其立方。但用解毒之品。未尝以桂附姜茱治阴。芩连硝黄治阳也。后世名家不深察仲景
之旨。遂以阳毒为阳症之甚者。而用寒凉。阴毒为阴症之甚者。而用温热。殊不知仲景论疗
阳症。状极其热。而药极其寒。论疗阴症。状极其寒。而药极其热。已无余蕴。而何必别出
名色乎。至其治阳毒。反投蜀椒者。椒本解毒之品。从其类而治之也。阴毒反去蜀椒者。为
升麻鳖甲。既属清凉。只觉蜀椒为赘矣。若以阳毒为极热。何不投凉剂而反入蜀椒耶。若以阴毒
为极寒。何不投温剂而反去蜀椒耶。是知如上五症。皆奇异而罕觏者。此金匮总类于一条之
中。良有说也。故凡学人。读前贤之书。不得草草看过。必深思而明辨之。庶乎入仲景之室
耳。
我曾阅读仲景的著作，读到《金匮要略》第三篇时，发现他将阴阳二毒的症状附在百合、狐惑、目赤黑病症之后。反复研读后，我得知这五种病症都是奇特的病证。
百合病的表现是：想吃却吃不下，想睡却睡不着，想走却走不动，好像冷又不冷，好像热又不热，症状怪异如同神灵作祟，多么奇特啊。
狐惑病的表现是：沉默寡言想睡觉，眼睛却无法闭合；侵蚀咽喉称为“惑”，侵蚀阴部称为“狐”；面色一会儿红，一会儿黑，一会儿白，又多么奇特啊。
目赤黑的表现是：不发热却心烦意乱，沉默寡言想躺卧；发病三四天眼睛发红，七八天眼睛变黑，又多么奇特啊。
阳毒的症状是面红如锦缎，咽喉疼痛，吐血；阴毒的症状是面目都发青，咽喉疼痛，身体像被棍棒打过一样疼痛。这两种病都在五天内可以治疗，七天后则难以治愈。然而在治疗上，这两种病都使用升麻鳖甲汤，这就让人无法理解了。对于阳毒的热证，反而加入蜀椒；对于阴毒的寒证，反而去掉蜀椒，这就更加令人不解了。
细究其叙述阳毒的内容，不过说面红、咽痛、吐脓血罢了，并没有描述亢盛至极的热象。叙述阴毒的内容，不过说面青、咽痛、身体像被杖击罢了，并没有描述极至的寒象。所用的方剂，不过是升麻、甘草、鳖甲、当归罢了，并没有使用大寒或大热的药物。
由此可知，仲景所说的阳毒，是感受天地恶毒的异气侵入阳经，就称为阳毒；侵入阴经，就称为阴毒。因此他创立的方剂，只使用解毒的药物，从未用桂枝、附子、干姜、吴茱萸来治疗阴毒，也未用黄芩、黄连、芒硝、大黄来治疗阳毒。
后世的名医没有深入考察仲景的本意，于是把阳毒当作阳证中严重的类型，而使用寒凉药物；把阴毒当作阴证中严重的类型，而使用温热药物。殊不知仲景论述治疗阳证，症状极其热，药物极其寒；论述治疗阴证，症状极其寒，药物极其热，已经穷尽了其中的道理，何必再另立名目呢？
至于治疗阳毒，反而投入蜀椒，是因为蜀椒本是解毒的物品，顺着它的性质来治疗它。治疗阴毒反而去掉蜀椒，是因为升麻鳖甲汤既属于清凉之剂，只觉得蜀椒多余罢了。如果把阳毒看作极热，为什么不投用凉剂反而加入蜀椒呢？如果把阴毒看作极寒，为什么不投用温剂反而去掉蜀椒呢？
因此知道以上五种病症，都是奇异且罕见的。这些病症在金匮要略中被归总在同一条文中，确实是有深意的。所以凡是学习的人，阅读前贤的书籍，不能草率看过，必须深思并明辨其理，这样才能进入仲景学术的门径。
I once read Zhang Zhongjing's works. Upon reaching the third chapter of *Jingui Yaolue* (Essential Prescriptions from the Golden Cabinet), I noticed that he appended the symptoms of Yin and Yang Du (Poison) to the end of the sections on Baihe Disease (Lily Disease), Huhuo Disease, and Red/Black Eyes. After repeated study, I realized that these five conditions are all rare and peculiar syndromes.
The presentation of Baihe Disease (Lily Disease) is such: the patient desires to eat but cannot, desires to sleep but cannot, desires to walk but cannot; it seems cold yet there is no coldness, seems hot yet there is no heat; the condition appears as if possessed by spirits, how peculiar it is.
The presentation of Huhuo Disease is such: the patient is taciturn and desires to sleep, yet eyes cannot close; erosion of the throat is called "Huo" (Charm), erosion of the yin organs is called "Hu" (Fox); the face alternates between red, black, and white, how peculiar it is.
The presentation of Red/Black Eyes is such: there is no fever yet there is vexation, the patient is taciturn and desires to lie down; on the third or fourth day, the eyes turn red; on the seventh or eighth day, they turn black, how peculiar it is.
Yang Du (Yang Poison) presents with a face red as brocade, sore throat, and hematemesis (vomiting blood). Yin Du (Yin Poison) presents with both face and eyes turning blue/green, sore throat, and body pain as if beaten with a stick. Both can be treated within five days, but are incurable after seven days. However, in treatment, both syndromes use Shengma Biejia Tang (Cimicifugae Rhizoma and Tortoise Shell Decoction), which is inexplicable. For the heat of Yang Du, Shuzhuo (Sichuan Pepper) is added; for the cold of Yin Du, Shuzhuo is removed, which is even more inexplicable.
Examining the description of Yang Du, it merely mentions a red face, sore throat, and expectoration of pus and blood, without describing signs of extreme hyperthermia. The description of Yin Du merely mentions a blue face, sore throat, and body pain as if beaten, without describing signs of extreme hypothermia. The prescribed formula consists only of Shengma (Cimicifugae Rhizoma), Gancao (Glycyrrhizae Radix et Rhizoma), Biejia (Testudinis Carapax et Plastrum), and Danggui (Angelicae Sinensis Radix), without using drugs of extreme cold or extreme heat.
Thus, we understand that what Zhongjing calls Yang Du is when one contracts the malignant qi of heaven and earth into the Yang meridians; if it enters the Yin meridians, it is called Yin Du. Therefore, his formulas only employ detoxifying herbs; he never used Guizhi (Cinnamomi Ramulus), Fuzi (Aconiti Lateralis Radix Praeparata), Ganjiang (Zingiberis Rhizoma), or Wuzhuyu (Evodiae Fructus) to treat Yin Du, nor Huangqin (Scutellariae Radix), Huanglian (Coptidis Rhizoma), Xiaoshi (Natrii Sulfas), or Dahuang (Rhei Radix et Rhizoma) to treat Yang Du.
Later famous physicians failed to deeply investigate Zhongjing's intent. Consequently, they regarded Yang Du as a severe form of Yang syndrome and used cold-cooling herbs; they regarded Yin Du as a severe form of Yin syndrome and used warm-warming herbs. Little did they know that when Zhongjing discussed treating Yang syndromes, the symptoms were extremely hot and the medicines extremely cold; when discussing treating Yin syndromes, the symptoms were extremely cold and the medicines extremely hot, leaving nothing further to be said. Why create separate categories?
Regarding the treatment of Yang Du, adding Shuzhuo (Sichuan Pepper) is because Shuzhuo itself is a detoxifying agent, treating it according to its nature. Removing Shuzhuo in the treatment of Yin Du is because Shengma Biejia Tang is already cooling, making Shuzhuo seem superfluous. If Yang Du were considered extreme heat, why not administer a cooling formula but instead add Shuzhuo? If Yin Du were considered extreme cold, why not administer a warming formula but instead remove Shuzhuo?
Therefore, it is known that the above five conditions are all rare and unusual. It is indeed meaningful that Jingui Yaolue groups them under one section. Thus, any student reading the books of former sages must not skim over them casually but must think deeply and discriminate clearly, so as to enter the chamber of Zhongjing's scholarship.