昔人有云，我但卧病，即于胸前不时手写死字，则百般思虑俱息，此心便得安静，胜于服药，此真无
上妙方也。盖病而不慎，则死必至。达此理者，必能清心克己，凡百谨慎，而病可获痊。否则虽有良
药，无救也。世人遇病而犹恣情任性，以自戕贼者，是固不知畏死者矣。又有一等明知畏死，而怕人知
觉，讳而不言，或病已重，而犹强作轻浅态度以欺人者，斯又知畏死而反以取死，尤可笑哉！
愚按心之官则思。而脾则主于思。病者有思，则
心火妄动，而五火翕然随之，脾气益伤，诸脏仍病。故书死字以自譬，则百虑息而天君泰然，虽有疾病，
勿药自愈矣。故古人谓讳疾忌医，骄恣不论于理之类，为不治之疾，有由然矣。
世间发热症，类伤寒者数种，治各不同，外感、内伤乃大关键。张仲景论伤寒、伤风，此外感也。因
风寒之邪感于外，自表入里，故宜发表以解散之，此麻黄、桂枝之义也。以其感于冬春之时寒冷之月，即
时发病，故谓之伤寒，而药用辛热以胜寒；若时非寒冷，则药当有变矣。如春温之月，则当变以辛凉之
药∶如夏暑之月，则当变以甘苦寒之药。故云冬伤寒不即病，至春变温，至夏变热，而其治法，必因时而
有异也。又有一种冬温之病，谓之非其时而有其气，盖冬寒时也，而反病温焉，此天时不正，阳气反泄，用
药不可温热。又有一种时行寒疫，却在温暖之时，时行温暖，而寒反为病，此亦天时不正，阴气反逆，用
药不可寒凉。又有一种天行温疫热病，多发于春夏之间，沿门阖境相同者，此天地之疠气，当随时令参气
运而施治，宜用刘河间辛凉甘苦寒之药，以清热解毒。以上诸症，皆外感天地之邪者。
若夫饮食、劳倦，为内伤元气，此则真阳下陷，内
生虚热，故东垣发补中益气之论，用人参、黄 等甘温之药，大补其气而提其下陷，此用气药以补气之不足
者也。又若劳心好色，内伤真阴，阴血既伤，则阳气偏胜而变为火矣，是谓阴虚火旺劳瘵之症，故丹溪发阳
有余阴不足之论，用四物加黄柏、知母，补其阴而火自降，此用血药以补血之不足者也。益气补阴，皆内伤症
也。一则因阳气之下陷，而补其气以升提之；一则因阳火之上升，而滋其阴以降下之∶一升一降，迥然不同矣。
又有夏月伤暑之病，虽属外感，却类内伤，与伤寒大异。盖寒伤形，寒邪客表有余之症，故宜汗之；
暑伤气，元气为热所伤而耗散不足之症，故宜补之，东垣所谓清暑益气者是也。又有因时暑热，而过食冷物
以伤其内，或过取凉风以伤其外，此则非暑伤人，乃因暑而自致之之病，治宜辛热解表，或辛温理中之药，
却与伤寒治法相类者也。凡此数症，外形相似，而实有不同，治法多端而不可或谬。故必审其果为伤寒、
伤风及寒疫也，则用仲景法；果为温病及瘟疫也，则用河间法；果为气虚也，则用东垣法；果为阴虚也，
则用丹溪法。如是则庶无差误以害人矣。
今人但见发热之证，一皆认作伤寒外感，率用汗药以发其表，汗后不解，又用表药以凉其肌，设是虚
证，岂不死哉？间有颇知发热属虚而用补药，则又不知气血之分，或气病而补血，或血病而补气，误人多
矣。故外感之与内伤，寒病之与热病，气虚之与血虚，如冰炭相反，治之若差，则轻病必重，重病必死
矣，可不畏哉！凡酒色过度，损伤脾肾真阴，咳嗽吐痰，衄血，吐血，咳血，咯血等症，误服参、
等甘温之药，则病日增，服之过多则不可治。盖甘温助气，气属阳，阳旺则阴愈消。前项病症，乃
阴血虚而阳火旺，宜服苦甘寒之药以生血降火。世人不识，往往服参、 以为补，予见服此而死者多矣。
愚按前论治验，见于各类。
古人曾说，我只要生病，就在胸前不时手写一个“死”字，这样各种思虑都会停止，内心就能得到安宁，这比服药还要好，这真是无上的妙方。因为患病如果不谨慎对待，死亡必然到来。明白这个道理的人，一定能清心寡欲、克制私欲，凡事都小心谨慎，疾病就可以痊愈。否则，即使有良药，也无法挽救。世上有些人遇到生病还放纵情欲、任性妄为，从而自我残害的，这确实是不懂得畏惧死亡的表现。又有一类人明明知道畏惧死亡，却怕别人察觉，隐瞒病情不说，或者病已经很重了，还强装出轻浅的样子来欺骗他人，这些人虽然知道畏惧死亡，反而因此招致死亡，更是可笑啊！
我认为心的功能是思考，而脾也主司思考。病人如果有过多的思虑，就会导致心火妄动，五脏之火随之一起燃烧，脾气更加受伤，其他脏腑依然患病。所以写“死”字来自我警示，使各种思虑平息，心神安定，即使有疾病，不服药也能自愈。所以古人说讳疾忌医、骄横放肆不讲道理等，是不治之症，是有原因的。
世间发热病症，类似伤寒的有好几种，治疗方法各不相同，外感和内伤是大的关键。张仲景论述伤寒、伤风，属于外感。因为风寒邪气从外部侵袭，由表入里，所以适宜用发汗解表的方法来解散它，这就是麻黄汤、桂枝汤的意义所在。因为它们是在冬春寒冷月份感受邪气并即时发病，所以称为伤寒，用药应当用辛热性质的药物来战胜寒邪；如果时间不是寒冷的，那么用药就应当改变。比如春季温暖的月份，就应当改用辛凉性质的药物；夏季暑热的月份，就应当改用甘苦寒性质的药物。所以说冬天感受寒邪没有立即发病，到了春天变成温病，到了夏天变成热病，而治疗方法，必须因季节不同而有差异。又有一种冬季发生的温病，叫做“非其时而有其气”，意思是冬天本是寒季，却反而发生温病，这是天时不正，阳气反而泄露，用药不可用温热性质。又有一种季节性寒疫，却在温暖的时候发生，本该温暖，寒气反而致病，这也是天时不正，阴气反而逆乱，用药不可用寒凉性质。又有一种流行性瘟疫热病，多发生在春夏之间，家家户户都相同的，这是天地间的疠气，应当根据时令和运气学说来进行治疗，适宜使用刘河间（刘完素）提出的辛凉甘苦寒性质的药物，以清热解毒。以上这些病症，都是外感天地邪气的情况。
至于饮食不节、劳倦过度，导致内伤元气，这是真阳下陷，体内产生虚热，所以李东垣提出补中益气的理论，用人参、黄芪等甘温性质的药物，大补元气并提升下陷之气，这是用补气药来补充气的不足。又如劳心过度、纵欲过度，内伤真阴，阴血既然受伤，阳气就会偏胜而变为火，这叫做阴虚火旺的劳瘵病症，所以朱丹溪提出“阳有余阴不足”的理论，使用四物汤加黄柏、知母，滋补阴液而火自然下降，这是用补血药来补充血的不足。益气补阴，都属于内伤病症。一种是因为阳气下陷，而补气以提升；一种是因为阳火上炎，而滋阴以降火：一升一降，截然不同。
又有夏季伤暑的病，虽然属于外感，却类似内伤，与伤寒大不相同。因为寒邪伤害形体，寒邪客居体表属于有余的实证，所以适宜发汗；暑邪伤害气机，元气被热邪所伤而耗散属于不足的虚证，所以适宜补益，这就是李东垣所说的清暑益气的方法。又有因为时令暑热，而过食冷物损伤内脏，或过度贪凉风损伤体表，这并非暑邪伤人，而是因为暑天自己导致的病，治疗适宜用辛热解表，或辛温理中的药物，这与伤寒的治疗方法相似。凡是这些病症，外形相似，但实质不同，治疗方法多样而不能有误。所以必须仔细审察究竟是否为伤寒、伤风及寒疫，如果是，就用张仲景的方法；究竟是温病及瘟疫，就用刘河间的方法；究竟是气虚，就用李东垣的方法；究竟是阴虚，就用朱丹溪的方法。像这样，或许就不会有差错而害人了。
现在的人只见发热症状，一律认作伤寒外感，随意用发汗药来发散表邪，发汗后不解，又用解表药来凉肌，如果是虚证，岂不死了吗？偶尔有人颇知发热属于虚证而用补药，却又不知道气血的区别，或者是气病却补血的，或者是血病却补气的，误人很多。所以外感与内伤，寒病与热病，气虚与血虚，如同冰炭相反，治疗如果有差错，轻病一定会加重，重病一定会死亡，能不害怕吗！凡是酒色过度，损伤脾肾真阴，出现咳嗽吐痰、鼻出血、吐血、咳血、咯血等症状，误服人参、黄芪等甘温性质的药物，则病情日益加重，服用过多则无法医治。因为甘温助长气，气属阳，阳气旺盛则阴液更加消损。上述病症，乃是阴血虚而阳火旺，适宜服用苦甘寒性质的药物来生血降火。世人不认识这一点，往往服用人参、黄芪以为补益，我见到服用这些而死的人很多了。
我认为前面的论述和治疗验证，见于各类医案中。
Ancient people once said, "Whenever I fall ill, I constantly write the character 'death' (Si) on my chest. This causes all kinds of thoughts and worries to cease, allowing the mind to find peace. This is superior to taking medicine; it is truly a supreme miraculous prescription." The reason is that if one does not exercise caution when ill, death will inevitably follow. Those who understand this principle can surely purify their hearts and restrain their desires, exercising caution in all matters, thereby achieving recovery from illness. Otherwise, even with good medicine, there is no salvation. Some people in the world, upon falling ill, indulge their passions and act arbitrarily, thus harming themselves; this is indeed ignorance of the fear of death. There is another group who, knowing well they should fear death, are afraid others will perceive their condition, so they conceal it and do not speak of it, or when the illness is already severe, they force a light attitude to deceive others. These people, though knowing to fear death, instead bring about their own demise, which is even more laughable!
I hold that the function of the Heart is thought, and the Spleen also governs thought. If a patient engages in excessive thinking, it causes the Heart Fire to move recklessly, and the Fires of the Five Zang Organs rise together, further injuring the Spleen Qi, while other organs remain diseased. Therefore, writing "death" serves as a self-admonition; when all worries cease and the Heavenly Ruler (Mind/Shen) is tranquil, even if disease exists, healing occurs without medication. Thus, ancient people stated that concealing illness and refusing medical help, or being arrogant and unreasonable, constitute incurable diseases, and this has its reasons.
Among fever syndromes in the world, several resemble Taiyang Disease (Shanghan). Their treatments differ significantly, with External Contraction (Wai Gan) and Internal Injury (Nei Shang) being the key distinctions. Zhang Zhongjing's discussion of Shanghan (Cold Damage) and Shangfeng (Wind Strike) belongs to External Contraction. Because Wind-Cold pathogens invade from the exterior and move from the surface inward, treatment should employ methods to release the exterior and disperse the pathogen; this is the rationale behind Mahuang Tang (Ephedra Decoction) and Guizhi Tang (Cinnamon Twig Decoction). Since these illnesses occur immediately after exposure during the cold months of winter and spring, they are termed Shanghan, and medicinal use should employ acrid-hot substances to overcome the cold. If the season is not cold, the medication must change. For example, in the warm month of spring, acrid-cool medicines should be used; in the hot month of summer, sweet-bitter-cold medicines should be used. Hence it is said: "Winter Cold Damage that does not manifest immediately may transform into Warm Disease in spring and Heat Disease in summer," and treatment methods must vary according to the season. Another type is Winter Warm Disease, described as "having the qi of a different season"; although winter is the time of cold, warmth disease occurs instead. This indicates improper heavenly timing where Yang Qi leaks abnormally; medications should not be warm or hot. Another type is seasonal Cold Epidemic, occurring during warm times. Although warmth prevails, cold becomes the pathogen due to improper heavenly timing where Yin Qi rebels abnormally; medications should not be cold or cool. Another type is the Tianxing Wenyi (Seasonal Warm Epidemic) Heat Disease, which often occurs between spring and summer, affecting entire households similarly. This is caused by Liqi (Miasma/Qi of Pestilence) of Heaven and Earth; treatment should consider the seasonal climate and Yùn (Luck/Cycle) theory, employing acrid-cool, sweet-bitter-cold medicines proposed by Liu Hejian (Liu Wansu) to clear heat and detoxify. All the above conditions involve external contraction of Heaven and Earth pathogens.
Regarding dietary irregularities and fatigue leading to Internal Injury of Yuan Qi (Original Qi), this involves the sinking of True Yang and the internal generation of Deficiency Heat. Therefore, Li Dongyuan proposed the theory of Bu Zhong Yi Qi Tang (Tonify the Middle and Augment the Qi Decoction), using sweet-warm medicines such as Renshen (Ginseng Radix) and Huangqi (Astragali Radix) to greatly tonify Qi and lift the sinking Qi. This uses Qi-tonifying herbs to supplement Qi deficiency. Furthermore, mental overwork and sexual excess cause Internal Injury to True Yin. Once Yin Blood is damaged, Yang Qi becomes hyperactive and transforms into Fire. This is termed Yin Deficiency with Hyperactive Fire, characteristic of Laozha (Consumption) syndrome. Therefore, Zhu Danxi proposed the theory of "Yang Excess and Yin Insufficiency," using Siwu Tang (Four Substances Decoction) plus Huangbai (Phellodendri Cortex) and Zhimu (Anemarrhenae Rhizoma) to nourish Yin, causing Fire to descend naturally. This uses Blood-nourishing herbs to supplement Blood deficiency. Tonifying Qi and Nourishing Yin both belong to Internal Injury syndromes. One treats sinking Yang Qi by tonifying Qi to lift it; the other treats rising Yang Fire by nourishing Yin to descend it. One lifts, one descends; they are completely different.
There is also Summerheat Injury occurring in summer. Although it belongs to External Contraction, it resembles Internal Injury and differs greatly from Shanghan. Cold damages the Form; Cold pathogens lodging in the exterior present as Excess syndromes, so sweating is appropriate. Summerheat damages Qi; Original Qi is damaged by Heat, leading to consumption and insufficiency (Deficiency syndromes), so tonification is appropriate. This is what Li Dongyuan referred to as Qing Shu Yi Qi (Clearing Summerheat and Augmenting Qi). Additionally, due to seasonal summer heat, overconsumption of cold foods damages the interior, or excessive exposure to cool winds damages the exterior. This is not Summerheat harming the person, but self-inflicted illness due to the summer context. Treatment should employ acrid-hot exterior-releasing or acrid-warm middle-regulating medicines, similar to Shanghan treatment methods. In all these cases, the external manifestations are similar, but the realities differ; treatment methods are diverse and must not err. Therefore, one must carefully examine whether it is truly Shanghan, Shangfeng, or Cold Epidemic; if so, use Zhang Zhongjing's method. If it is Warm Disease or Plague, use Liu Hejian's method. If it is Qi Deficiency, use Li Dongyuan's method. If it is Yin Deficiency, use Zhu Danxi's method. Only then can errors that harm people be avoided.
Today, people see fever symptoms and uniformly classify them as Shanghan External Contraction, rashly using diaphoretic drugs to release the exterior. If the fever persists after sweating, they use exterior-releasing drugs to cool the muscles. If the case is actually Deficient, would this not lead to death? Occasionally, some know that fever belongs to Deficiency and use tonifying drugs, yet they fail to distinguish between Qi and Blood. They may tonify Blood for Qi disorders, or tonify Qi for Blood disorders, misleading many. Thus, External Contraction vs. Internal Injury, Cold Disease vs. Heat Disease, Qi Deficiency vs. Blood Deficiency are like ice and charcoal opposing each other. If treatment errs, mild diseases will become severe, and severe diseases will lead to death. Should one not fear this? Cases of excessive alcohol and sex damaging the True Yin of the Spleen and Kidney, presenting with coughing and expectoration, epistaxis, hematemesis, hemoptysis, and spitting blood, if mistakenly administered sweet-warm medicines like Renshen (Ginseng Radix) and Huangqi (Astragali Radix), will result in worsening conditions daily. Overconsumption renders them untreatable. Sweet-warm substances aid Qi; Qi belongs to Yang. When Yang is vigorous, Yin is further depleted. The aforementioned conditions involve Yin-Blood Deficiency and Yang-Fire Hyperactivity; bitter-sweet-cold medicines should be taken to generate Blood and descend Fire. People of the world do not recognize this, often taking Renshen and Huangqi as tonics. I have seen many die from taking these.
I maintain that the preceding discussions and treatment validations appear in various categories.