仲景论两感伤寒云。凡伤于寒热。虽甚。不死。若两感于寒而病者。必死。又云两感病俱作。治有先后。发表
攻里。本自不同。既云必死。又云治有先后。何也。大抵此病表里双传。脏腑俱受。得此者十不全一。故云必
死。然仲景岂以己见而重诬后人哉。故有发表攻里之说。以勉后世。恐万世之下。一遇大圣而得之者。不
欲绝望于后人也。则仲景仁心可知矣。
伤寒不问阴证阳证。阴毒阳毒。要之真气完壮者易医。真气虚损者难治。谚云伤寒多死下虚人。诚哉是
言也。盖病患元气不固。真阳不完。受病才重。便有必死之道。何也。阳病宜下。真气弱则下之多脱。阴病宜
温。真气弱则客热便生。故医者难于用药。非病不可治也。主本无力也。素问称岐伯云。阳胜则身热腠理
闭。喘粗。为之俯仰。汗不出而热。齿干以烦冤腹满死。能（能音耐）。冬不能夏。阴胜则身寒汗出。身常清。
数栗而寒。寒则厥。厥则腹满死。能夏不能冬。黄帝曰。调此二者奈何。岐伯曰。能知七损八益。则二者可调。
盖阳胜而汗不出者。伤寒也。阴胜身寒而汗出者。中风也。二者须知七损八益而已。盖女子二七天癸至。至七七
止。男子二八精气溢。至八八而止。妇人月事以时下。故七欲损。男子精欲满而不竭。故八欲溢。如此则男
子女人身常无病也。自身无病。真气完固。虽有寒邪。易于用药。故曰二者可调。是知伤寒以真气为主。
张仲景在论述两感伤寒时说：“凡是感受寒热邪气，即使病情严重，也不会死亡；如果是两感于寒而发病的，必定死亡。”他又说：“两感病同时发作，治疗有先后顺序之分，解表与攻里，原本就是不同的方法。”既然说“必定死亡”，又说“治疗有先后顺序”，这是为什么呢？大抵这种病是表里同时传变，脏腑都受到侵害，得此病的人十个里面活不到一个，所以说必定死亡。然而，张仲景难道是用自己的主观见解来重重地诬蔑后人吗？所以才有了解表攻里的说法，以此来勉励后世医生，恐怕在万世之后，如果遇到圣人般的医生能够治愈此病，不希望让后人对治病失去信心。由此可知张仲景的仁爱之心了。
伤寒病不分阴证阳证、阴毒阳毒，总之真气完足强壮的人容易医治，真气虚损的人难治。谚语说：“伤寒多死于下元虚损之人。”这句话说得确实正确啊。大概是因为病人元气不固，真阳不完备，刚受病邪侵袭且病情稍重，就有必死的趋势。为什么呢？阳证适宜用下法，但真气虚弱时如果用下法，大多会导致正气脱失；阴证适宜用温法，但真气虚弱时如果用温法，就会产生客热（外来的热邪）。所以医生难以用药，并不是病不可治，而是患者本身体质无力承受。《素问》记载岐伯说：“阳气偏胜则身体发热，腠理闭塞，呼吸喘促粗重，身体俯仰不安，汗不出而身热，牙齿干燥，心中烦闷痛苦，腹部胀满而死，能耐受冬季而不能耐受夏季。”（“能”通“耐”）。“阴气偏胜则身体寒冷，出汗，身体经常清冷，频繁战栗发冷，寒冷导致四肢厥逆，厥逆则腹部胀满而死，能耐受夏季而不能耐受冬季。”黄帝问：“调和这两者该怎么办？”岐伯说：“如果能懂得‘七损八益’的道理，那么这两者就可以调和。”大概阳气偏胜而汗不出的是伤寒，阴气偏胜身体寒冷而出汗的是中风。这两种情况都需要懂得“七损八益”的道理罢了。大概女子十四岁天癸至，到四十九岁停止；男子十六岁精气溢泻，到六十四岁停止。妇女月经按时来潮，所以“七”要减损；男子精气要充盈而不枯竭，所以“八”要溢满。像这样，男女的身体就常常没有疾病了。自身没有疾病，真气完固，虽然有寒邪侵袭，也易于用药治疗。所以说这两者可以调和。由此可知，治疗伤寒以真气为主。
Zhang Zhongjing discussed Lianggan Shanghan (Two-Aspect Cold Damage) stating: "For those injured by cold and heat pathogens, even if severe, they will not die. However, for those suffering from Lianggan on Han (simultaneous invasion of exterior and interior by cold), the outcome is fatal." He further stated: "When Lianggan disease occurs simultaneously, treatment must follow a specific sequence; releasing the exterior and purging the interior are fundamentally different approaches." If it is said that death is inevitable, yet there is a sequence of treatment, why is this? Generally, this disease involves simultaneous transmission of the exterior and interior, affecting both zang and fu organs. Fewer than one in ten survive, hence the statement of fatality. Yet, would Zhang Zhongjing falsely mislead future generations with his own views? Thus, he proposed methods of releasing the exterior and purging the interior to encourage later physicians, hoping that in future ages, if a sage-like physician were to encounter such cases, humanity would not lose hope. This reveals Zhang Zhongjing's benevolent heart.
Shanghan (Cold Damage) does not distinguish between Yin syndromes and Yang syndromes, or Yin poison and Yang poison. Ultimately, patients with robust Zhenqi (True Qi / Vital Energy) are easier to treat, while those with deficient Zhenqi are difficult to treat. The proverb states, "Shanghan often kills those with deficiency in the lower jiao (lower abdomen/kidneys)." This is indeed true. Generally, when a patient's Yuanqi (Original Qi) is insecure and True Yang is incomplete, even a slight onset of disease can lead to a fatal trajectory. Why? For Yang syndromes, purgation is indicated; however, if Zhenqi is weak, purgation often leads to collapse of Zhengqi (Upright Qi). For Yin syndromes, warming is indicated; however, if Zhenqi is weak, warming may generate Ke Re (Guest Heat / Exogenous Heat). Therefore, physicians find it difficult to administer medication, not because the disease is incurable, but because the patient's constitution lacks the strength to withstand treatment. The Suwen (Classic of Difficult Issues) records Qibo saying: "Excess Yang results in fever, closed pores, coarse breathing, restlessness, absence of sweat despite heat, dry teeth, vexation, abdominal fullness leading to death; these patients can endure winter but not summer." ("Neng" means "endure"). "Excess Yin results in cold body, sweating, constant chilliness, frequent shivering and coldness, cold leading to Jue (Reversal/Cold extremities), Jue leading to abdominal fullness and death; these patients can endure summer but not winter." The Yellow Emperor asked, "How should these two be regulated?" Qibo replied, "If one understands the principles of Seven Losses and Eight Gains, these two can be regulated." Generally, excess Yang with no sweat characterizes Shanghan; excess Yin with cold body and sweat characterizes Fengzhong (Wind Strike). Both require understanding the principles of Seven Losses and Eight Gains. Specifically, women experience Tian Gui (Menstruation/Reproductive Essence) at age fourteen (2x7) and cease at forty-nine (7x7); men have abundant Jing (Essence) at sixteen (2x8) and cease at sixty-four (8x8). Women's menstruation arrives regularly, so the number seven implies loss/reduction; men's Jing should be full and not depleted, so the number eight implies overflow. In this manner, men and women remain healthy. With a healthy body and solid Zhenqi, even if invaded by cold pathogens, medication is easily administered. Thus, it is said that these two can be regulated. From this, we know that treating Shanghan prioritizes Zhenqi.