医之为道。肇始于本草经。阐明于素难。至伤寒论而大备焉。本草经者神农氏之书也。素难
者轩岐越人之书也。伤寒论仲景氏之遗书也。然本草之作于神农氏。世传其说而不经见。嘉 本草
序谓。神农尝百草而医方兴。上世未有文本。师学相传。谓之本草。两汉名医仲景华佗诸贤。始
因古学附以新说。通为编述。本草由是始见于经。诚如是。仲景既已首事其间。而乃有是论之作。
则其先后素难而股肱之。其功岂不远贤于神皇轩岐与越人而独盛哉。于是医门尊之以为圣。犹儒
门之圣孔子而宗师焉。然则斯道之大。其所以继往圣而开来学人。顾不大有赖于斯文邪。夫道不
出自圣人不足以言大。何谓大道。道莫大于尧舜。孔子之赞尧。则曰巍巍乎惟天为大。惟尧则之。
孔子簇圣之大成。子贡之赞孔子。则曰夫子之不可及也。犹天之不可阶而升也。然则圣人之所
以大。无有不出自天者。噫本草之作于神农氏。继天而立极者也。素难之作于轩岐越人。启天人
之秘也。是论也本之风暑湿寒。发之于三阳三阴。风暑湿寒者天之四气也。三阳三阴者。人之所得
乎天。周于身之六经也。四气有时或不齐。六经因之而为病。是故病统乎经。中伤合并。脉证传变。
标本虚实。表里寒热。汗吐下温。正反逆从条。之以法。而法三百九十七系之以方。而方一百一十
三者。天人事物错综之自然而然者也。其以风为首论者。即素曰风为首百病之长之意也。其推而至
于坏病。不以病名名病。而以坏名者。坏则不能尽其变。而举以名之。故概之以坏。曰坏者。即素
问曰万病皆生于风寒暑湿燥火之意也。自其析而言之。诚万殊也。然既坏矣。而曰知犯何逆。随
证治之。知犯何逆。以法治之。其所以妙于一本者。岂小道者所可得同日而语哉。读之者皆知其
为伤寒论也。而不知其乃有所为于伤寒而立论。所论不啻伤寒而已也。本草素难之显仁藏用者。
表表然无余蕴矣。所以法而世为天下则。方而世为万病祖。乃至预有集斯道之大成。而擅百世宗
师之同归者。道不同而同出于天。天者理也。理在人心。无古今方隅之异也。何则乃有不同是心。
不宗师斯。而铃捶活人类证焉。铃捶活人类证者出。而斯道日茅塞矣。继素难之往辙。难乎其有
人焉。非天下之病。是病者有所不幸而然邪。何斯道之至于斯也。嗟乎七篇不作。杨墨之横流不
息也。濂洛关闽之传注不出。尧舜孔子之道家殊而户异也。是故义利之辩。图象性命之问难。其
所以为不得已者。易地则皆然也。余何人斯而条辨哉。盖将以为后之有志仲景之堂室者。级阶梯
之助云尔也。
时万历己丑春三月戍申朔新安方有执书
医学之道，始于《本草经》，阐发于《素问》与《难经》，至《伤寒论》而完备。《本草经》是神农氏的著作；《素问》与《难经》是黄帝、岐伯及秦越人（扁鹊）的著作；《伤寒论》是张仲景遗留下来的著作。然而，《本草经》成书于神农氏时代，世间流传其学说却不见于经典记载。《嘉本草序》中说：“神农品尝百草，医方由此兴起。”上古时代还没有文字记录，依靠师徒口耳相传，所以称为“本草”。到了两汉时期，名医张仲景、华佗等贤者，才开始依据古代学问，附以新的见解，通盘编纂叙述，《本草经》这才开始见于经典文献。如果确实如此，那么张仲景既然已经首先参与此事，又撰写了这部《伤寒论》，那么它是在《素问》《难经》之前，并作为它们的辅佐，其功劳难道不是远远超过神农、轩辕、岐伯和秦越人，而独自兴盛吗？因此，医学界尊奉它为圣人，就像儒家尊奉孔子为圣人并以其为师一样。既然如此，这门大道的伟大，它所继承前代圣贤并开启后世学者，难道不大有赖于这部著作吗？
大道如果不出自圣人，就不足以称为伟大。什么是大道？道没有比尧舜更大的了。孔子赞美尧，就说：“高大啊！只有天最高大，只有尧效法它。”孔子集圣人之大成，子贡赞美孔子，就说：“老师的不可企及，就像天无法通过阶梯攀登一样。”那么圣人的伟大，无不源自于天。唉！《本草经》由神农氏所作，是承接天命而立起准则；《素问》《难经》由轩辕、岐伯、秦越人所作，是开启了天人的奥秘。这部《伤寒论》本源于风、暑、湿、寒四气，将其发用于三阳经和三阴经。风、暑、湿、寒是天之四气；三阳三阴是人从上天所得，周流于身体的六经之中。四气有时不协调，六经因此发生病变。所以疾病统属于经络，中伤合并，脉象与证候传变，标本虚实，表里寒热，汗、吐、下、温等治法，正反逆从，条分缕析地制定法则，共有三百九十七条法则，并以此系联方剂，共有方剂一百一十三首。这是天人人事物错综复杂的自然结果。之所以以“风”为首篇论述，就是《素问》所说“风为百病之长”的意思。它推演至于“坏病”，不以病名来命名疾病，而以“坏”来命名，是因为“坏”字不能穷尽所有的变化，所以举其大概命名为“坏”。所谓“坏”，即《素问》所说“万病皆生于风寒暑湿燥火”的意思。从分析的角度来说，确实是千差万别。但是既然已经坏了，就说“知道犯了什么错误（逆乱），根据证候治疗”，“知道犯了什么错误，用相应的法治它”。这种妙在“一本”（根本原则统一）的地方，难道是浅薄之人所能同日而语的？读书的人都知道这是《伤寒论》，却不知道它是有所针对“伤寒”而立的论说，所论述的不止是伤寒而已。《本草》《素问》《难经》显扬仁德、隐藏功用的道理，在这里表现得淋漓尽致，毫无保留。所以成为效法的准则，世代作为天下的榜样；成为方剂的祖源，世代作为万病的根源。以至于预先集此道之大成，享有百世宗师共同归宿的地位。道虽然不同，但同出于天。天就是理。理存在于人心，没有古今地域的差异。为什么会有不同呢？是因为心志不同，不尊奉这部经典为师，而是用铃捶之类的方法去救治人类、辨别证候。一旦出现了用铃捶救治人类、辨别证候的做法，这门大道就日益被堵塞不通了。继承《素问》《难经》的旧辙，很难再有人做到了。这不是天下的悲哀，而是患病者的不幸吗？为什么这门大道会沦落至此呢？唉！如果七篇（指《内经》中的七篇大论或相关经典篇章）不再出现，杨朱、墨翟的邪说横流不息，濂溪、洛阳、关中学派及闽学的传注不出，那么尧舜孔子的道就会家殊户异。因此，义与利的辩论，图像与性命之问难，那些不得已的原因，易地而处都是如此。我是什么人呢，却要来进行条辨呢？大概是打算为后来有志于进入张仲景堂室的人，提供登阶梯的帮助罢了。
时值万历己丑年春三月戊申朔日，新安方有执书写。
The Way of Medicine originated with the *Shennong Bencao Jing* (Divine Farmer's Materia Medica), was elucidated in the *Suwen* (Basic Questions) and *Nanjing* (Classic of Difficult Issues), and reached its completeness in the *Shanghan Lun* (Treatise on Cold Pathogenic Disorders). The *Shennong Bencao Jing* is the work of Shennong; the *Suwen* and *Nanjing* are the works of Huangdi (Yellow Emperor), Qibo, and Yue Ren (Bian Que); the *Shanghan Lun* is the surviving work of Zhang Zhongjing. However, the *Bencao Jing* was produced in the era of Shennong; although its theories are passed down in the world, they are not seen in the classics. The *Preface to Jia Bencao* states: "Shennong tasted hundreds of herbs, and medical formulas arose." In ancient times, there were no written texts; knowledge was transmitted orally from teacher to student, hence it was called "Bencao" (Herbal Classics). It was only during the Two Han Dynasties that famous physicians such as Zhang Zhongjing and Hua Tuo began to compile and narrate based on ancient learning, attaching new interpretations. Thus, the *Bencao Jing* first appeared in the classics. If this is true, since Zhang Zhongjing had already taken the lead in this matter, and then composed this *Shanghan Lun*, its precedence over the *Suwen* and *Nanjing* and its role as their support—was its merit not far surpassing that of Shennong, Xuanyuan (Huangdi), Qibo, and Yue Ren, standing alone in its prosperity? Therefore, the medical community reveres it as a Sage, just as the Confucian community reveres Confucius as the Sage and takes him as a model. Given this, how great is this Way! Does it not greatly rely on this text to succeed the sages of the past and open up learning for future generations?
A Great Way cannot be spoken of unless it originates from a Sage. What is the Great Way? No Way is greater than that of Yao and Shun. When Confucius praised Yao, he said: "How lofty! Only Heaven is great; only Yao modeled himself upon it." Confucius gathered the great achievements of all sages; when Zigong praised Confucius, he said: "The Master is unattainable, just as Heaven cannot be climbed by means of a ladder." Thus, the greatness of the Sages all stems from Heaven. Alas! The *Bencao Jing*, authored by Shennong, established standards by following Heaven. The *Suwen* and *Nanjing*, authored by Xuanyuan, Qibo, and Yue Ren, revealed the secrets of Heaven and Humanity. This treatise (*Shanghan Lun*) is rooted in Wind, Summer-heat, Dampness, and Cold; it manifests through the Three Yang and Three Yin meridians. Wind, Summer-heat, Dampness, and Cold are the Four Qi of Heaven; the Three Yang and Three Yin are what humans receive from Heaven, circulating through the Six Meridians of the body. When the Four Qi are out of harmony, the Six Meridians become diseased. Therefore, diseases are unified under the meridians; injuries combine, pulses and symptoms transmit, root and branch, deficiency and excess, interior and exterior, cold and heat are analyzed. Methods such as sweating, vomiting, purging, and warming, along with correct/reverse and following/opposing principles, are detailed in laws. There are 397 laws, linked to 113 formulas. This is the natural result of the intricate interplay of Heaven, Humanity, affairs, and things. The reason it begins with Wind is consistent with the statement in the *Suwen*: "Wind is the chief of a hundred diseases." It extends to "ruined diseases" (Huai Bing). Instead of naming diseases by their specific names, it uses the term "ruined" because "ruined" cannot exhaust all variations, so it uses this general term. "Ruined" corresponds to the meaning in the *Suwen*: "All diseases arise from Wind, Cold, Summer-heat, Dampness, Dryness, and Fire." Analytically speaking, they are indeed myriad and distinct. Yet, once ruined, one says, "Know what deviation has occurred, and treat according to the syndrome"; "Know what deviation has occurred, and apply the appropriate method." The subtlety of being unified in one fundamental principle—how can this be compared to the shallow understanding of minor paths? Readers know this is the *Shanghan Lun*, but do not realize that it was established specifically for "Cold Damage," and what it discusses is not limited to Cold Damage alone. The revealing of benevolence and hiding of utility found in the *Bencao*, *Suwen*, and *Nanjing* are here fully expressed without reserve. Thus, it serves as the law for the world and the ancestor of formulas for all diseases. It anticipates gathering the great achievements of this Way, sharing the common destination of being the grand master for a hundred generations. Although the Ways differ, they all originate from Heaven. Heaven is Principle (Li). Principle resides in the human heart, with no difference between ancient and modern times or directions. Why then are there differences? Because hearts differ; if one does not take this as a model, but instead uses bells and hammers to save humanity and classify syndromes, once such methods emerge, this Way will be increasingly blocked. To follow the tracks of the *Suwen* and *Nanjing*, it is difficult to find anyone. Is this not a sorrow for the world, and an unfortunate fate for those who are ill? Why has this Way fallen to this state? Alas! If the Seven Chapters (referring to key canonical texts) do not appear, and the rampant spread of Yang Zhu and Mo Di's teachings continues unchecked, and the commentaries of the Lian, Luo, Guan, and Min schools do not emerge, then the Way of Yao, Shun, and Confucius will diverge house by house. Therefore, the debate between righteousness and profit, and the inquiries into images and life-nature, are unavoidable reasons; if positions were exchanged, the situation would be the same. Who am I to conduct these line-by-line analyses? I merely intend to provide a stepping stone for those who come later and aspire to enter the halls of Zhang Zhongjing.
Written by Fang Youzhi of Xin'an on the first day (Wu Shen) of the third month of spring, in the Ji-Chou year of the Wanli reign.