世之重疾，无逾风、劳、臌、膈。而四者之治，总有蹊径可寻。如风症止真中、类中二条，
真中殊少，治法无多，止有类中亦不过气血亏损而已。故张景岳恐人认作风治，特立非风一门。
究其治法，惟大补气血而止。劳症即云难治，亦不过阴阳、水火、气血、先天、后天，视其何者
亏损而补益之。臌胀有驱水理气之殊，噎膈止润燥养血之法。惟至于疫，变化莫测，为症多端，
如神龙之不可方物。临症施治者，最不宜忽也。瘟疫尚好治疗，识其表里，已得大纲，即有变现
杂症，如斑汗、
发黄之类，皆易捉摸。即杂疫如所谓诸瘟、诸痧、诸挣等症，各具疗法，亦易施治。唯乙巳年，
民之所患并非奇疾怪症，不过痢疾、泄泻，肚腹胀痛等病，有何难疗？孰意用平日治此疾法治之，
半皆不应。或二三人同患一症而治法各异者，施之此人而效，施之彼人而又不效矣。或有一人患
是症而愈，而复作者，其治法又异，施之前次而效，施之后此而又不效矣。若非具慧眼卓识，而
窥见垣一方者，岂能人人而济之乎！盖必深明乎司天在泉之岁，正气客气之殊，五运六气之微，
阴阳四时之异，或亢旱而燥热烦灼，或霖雨而寒湿郁蒸，或忽寒而忽暖，或倏晴而倏阴，或七情
之有偏注，或六欲之有慝情，或老少强弱之异质，或富贵贫贱之殊途，细心入理，再加以望闻问
切，一一详参，庶病无遁情，而矢无妄发。至于治法，千变万化，随宜用药，莫可名言。故仲景
曰∶瘟疫不可先定方，瘟疫之来无方也，旨哉斯言。疫病一门，又岂一百一十三方所能尽哉！
是在留心此道者，神而明之可耳。
世间严重的疾病，没有超过风、劳、臌、膈这四种的。而这四种病的治疗，总有规律可循。比如风症（中风类疾病）只分为真中（外感风邪直中脏腑）和类中（内伤气血所致类似中风之证）两条路径，真中非常少见，治疗方法不多；类中也不过是气血亏损罢了。所以张景岳担心人们误将此类病症当作风邪来治疗，特意设立了“非风”这一门类。究其治疗方法，只是大补气血而已。
劳症（虚劳病）虽然号称难治，也不过是阴阳、水火、气血、先天、后天哪一方面亏损，就针对该方面进行补益。臌胀（鼓胀病）有驱除水湿、调理气机的不同治法，噎膈（吞咽困难、胸膈阻塞）只有滋润燥热、养血的方法。唯独到了疫病，变化莫测，症状繁多，像神龙一样无法预测。临证施治的人，最不应该忽视这一点。
瘟疫还算好治疗，只要识别出表证或里证，就已掌握了大纲，即使出现变症杂症，如发斑、出汗、发黄等，都容易把握。即使是杂疫，如所谓的各种瘟病、痧症、挣症等，各自都有相应的疗法，也容易施治。唯有乙巳年（指1665年或1905年等干支纪年），百姓所患并非奇奇怪怪的疾病，不过是痢疾、泄泻、肚腹胀痛等病，有什么难治疗的？没想到用平日治疗这些疾病的方法去治，半数都不见效。或者两三个人同患一种病症，但治疗方法却各不相同，对这个人有效，对那个人又无效了。或者有一个人患了这种病痊愈后，又复发的，治疗方法又不同，用前一次的方法有效，用后一次的方法又无效了。如果不是具备慧眼卓识，能洞察细微之处的人，怎么能人人救治呢！
这是因为必须深明司天在泉（运气学说中主管一年气候变化的因素）的岁运，正气与客气（正常气候与异常气候）的区别，五运六气（中医运气学说核心概念）的精微，阴阳四时（四季气候变化）的差异。或者是亢旱导致燥热烦灼，或者是霖雨导致寒湿郁蒸，或者是忽冷忽热，或者是忽晴忽阴，或者是七情（喜、怒、忧、思、悲、恐、惊）有所偏注，或者是六欲（眼、耳、鼻、舌、身、意对应的欲望）产生邪情，或者是老少强弱体质的差异，或者是富贵贫贱生活环境的殊途。细心探究医理，再加上望闻问切四诊，一一详细参详，这样病情就没有隐瞒的，用药也不会妄发。至于治疗方法，千变万化，随宜用药，不可用言语完全概括。所以张仲景说：“瘟疫不可以预先定方，瘟疫的到来是没有固定模式的”，这话真是精辟啊。疫病这一门类，难道是一百一十三首方剂所能穷尽的吗！这在于留心此道的人，能够神而明之即可。
Severe diseases in the world are surpassed by none other than Wind (Zhongfeng), Consumption (Lao), Distension (Gu), and Dysphagia (Ge). However, there are always patterns to be found in treating these four categories. For instance, Wind diseases are divided into only two types: True Wind Stroke (Zhenzhong, stroke caused by direct invasion of external wind pathogens) and Resembling Wind Stroke (Leizhong, stroke-like syndrome caused by internal deficiency of Qi and Blood). True Wind is extremely rare, with few treatment methods; Resembling Wind is merely a deficiency of Qi and Blood. Therefore, Zhang Jingyue feared that people might mistake this condition for Wind and specifically established a category called "Non-Wind." Ultimately, its treatment method consists solely of greatly tonifying Qi and Blood.
Consumption (Lao, chronic deficiency syndrome), although considered difficult to treat, involves merely identifying which aspect—Yin-Yang, Water-Fire, Qi-Blood, Congenital Essence, or Acquired Foundation—is deficient and tonifying it accordingly. Distension (Gu, abdominal distension with fluid accumulation) has distinct methods for driving out water and regulating Qi, while Dysphagia (Ge, difficulty swallowing and chest obstruction) relies on methods to moisten dryness and nourish Blood. Only when it comes to Epidemic Diseases (Yi), changes are unpredictable, and symptoms are manifold, like a divine dragon that cannot be grasped. Clinicians must not overlook this point.
Plague (Wenyi) is relatively easier to treat; once the Exterior or Interior pattern is identified, the general principle is grasped. Even if complicated symptoms arise, such as macules (Ban), sweating (Han), or jaundice (Huang), they are easy to manage. Even miscellaneous epidemics, such as various Plagues (Wen), Sha Syndrome (Sha), and Zheng Syndrome (Zheng), each have specific therapies and are relatively easy to treat. However, in the Yisi year, the ailments suffered by the people were not bizarre diseases, but simply dysentery (Liji), diarrhea (Xiexie), and abdominal distension and pain (Fuzhang Tongtong)—what could be more treatable? Unexpectedly, using the usual methods for these diseases resulted in half being ineffective. Sometimes two or three people suffered from the same symptom, yet the treatments differed; what worked for one person was ineffective for another. Or, a person recovered from a certain illness only to relapse, requiring a different treatment method; what worked previously was ineffective subsequently. Unless one possesses keen insight and discernment to perceive subtle details, how can everyone be saved?
This is because one must deeply understand the annual influences of Si Tian and Zai Quan (factors governing climate in Chinese medical astrology), the distinction between Zheng Qi (Correct Qi/Normal Climate) and Ke Qi (Guest Qi/Abnormal Climate), the subtleties of Wu Yun Liu Qi (Five Movements and Six Qi theory), and the variations of Yin-Yang across the four seasons. Whether due to extreme drought causing dry heat and vexation, or continuous rain causing cold-dampness stagnation, sudden cold or warmth, fleeting sunshine or gloom, bias in the Seven Emotions (Qi Qing), deviant desires of the Six Desires (Liu Yu), differences in constitution among the old, young, strong, and weak, or divergent paths of the rich, noble, poor, and humble—all require careful investigation into principles. Combined with Observation, Auscultation/Olfaction, Inquiry, and Palpation (Wang Wen Wen Qie), detailed analysis ensures no disease remains hidden and prescriptions are not issued arbitrarily. Treatment methods vary infinitely, adapting to circumstances, defying verbal description. Thus, Zhang Zhongjing stated: "Epidemics cannot be treated with pre-determined formulas; their arrival has no fixed pattern." This statement is profound. Can the category of Epidemic Diseases be exhausted by just 113 formulas! It depends on those attentive to this field to comprehend it spiritually and illuminate it.