瘴与疟。似同而实异。故瘴之轻者。全类疟疾。医者不知治瘴之法。例用常山白砒及草果。
涌吐其痰。致元气实者。荏苒难安。元气弱者。即加肿胀。多致不起。深可太息。盖瘴疾因阳气
不降又吐之。则不降之阳气愈升。中气愈虚。其不危者几希。故白砒草果毫不可用。若常山犹有
用处。其力能去皮肤毛孔中之瘴气。寒热所感。邪气多在荣卫及肉之间。欲除根本。非常山不可。然常
山多能吐。人须制之使不吐。方可用。七宝饮冷服之。不吐截疟丸。日服六七次。酒送之。亦不
吐。屡验之药也。当知此药乃末后之兵。方其瘴之始发。必先正气和解。温中镇下。固守乎病患
元元之气。兵法所谓避其来锐是也。及其热之间断也。明见其作息有时。一日一作。只有五六时即退。
或间一日一作。审知其脾胃已和。下焦湿冷已去。元气渐而平复。邪热渐微渐短。即用七宝饮
截疟丸。则应手而愈。兵法所谓击其惰归者。是也。苟不明此理。当其病热正盛。而用常山。则
非徒无益。而正气愈损矣。
瘴疾之作。率由暑热。所以腠理不密。多自汗。医者因其自汗。以治疟之法治之。用参 归术
之剂补之。服后愈觉烦闷难安。神识昏迷不知。天热气蒸。得雨方解。瘴病热蒸。烦汗方除。白术
止汗。黄 止汗。密腠理。汗不得出。热蒸无
由得解。更作烦闷神昏。故白术黄 亦不宜遽用。或曰白术黄 。其性敛汗。为不可用。而肉桂亦
非汗药。何又用之。余曰肉桂固能止汗。本草有曰主温中。又曰本乎地者。亲下。补肾用肉桂。故其
性亦能引上焦之阳气。下达肾经。故可用。或曰子言。天气热蒸。得雨方解。瘴病热蒸。得汗方除。
今病者自汗。宜其瘴之愈也。何又不除。余曰此自汗略得舒片时之热闷耳。若欲其愈。必也温中固下。
正气和解。使阴升阳降。荣卫和调。邪无容地。自然大汗如雨。自头至足。无处不出。大汗后浑
身冰冷。惟口中所出之气略温。此等证候不见。瘴热不复来矣。此时惟当慎其调摄。得百日。元气
可复常耳。
瘴病与疟疾，表面相似但实质不同。因此，轻度的瘴病完全类似疟疾。如果医生不了解治疗瘴病的方法，一律使用常山、白砒及草果，通过涌吐来祛除痰涎，会导致元气充实的患者病情迁延难愈，元气虚弱的患者则立即出现肿胀，大多导致死亡，实在令人叹息。这是因为瘴疾本身是因为阳气不降，如果再加以催吐，那么本就不降的阳气会更加上逆，中气更加虚弱，能够不危及生命的几率极小。所以白砒和草果绝对不可使用。至于常山，还有其用处，它的力量能去除皮肤毛孔中的瘴气，以及寒热感受到的邪气，这些邪气多在荣卫及肌肉之间，想要根除根本，非用常山不可。然而常山多能引起呕吐，人必须炮制它使其不致呕吐，才可以服用。可以用七宝饮冷服，或者截疟丸，每天服用六七次，用酒送服，也不会引起呕吐，这是经过多次验证有效的药物。应当知道这种药是最后的兵力（指最后手段）。在瘴病刚发作时，必须先调和正气，温中镇下，固守患者的元气，这就是兵法所说的“避开敌人初来时的锐气”。等到发热间歇期，明确看到它有规律，一天发作一次，只持续五六个小时就退去，或者隔天发作一次，确认脾胃已经调和，下焦湿冷已去，元气逐渐平复，邪热逐渐微弱短暂，这时就用七宝饮或截疟丸，就能手到病除，这就是兵法所说的“攻击敌人懈怠归来的时机”。如果不明白这个道理，在病热正盛的时候使用常山，不仅无益，反而会使正气更加受损。
瘴疾的发生，通常由于暑热，所以腠理不紧密，容易自汗。医生因为患者自汗，就用治疗疟疾的方法来治疗，用人参、当归、白术等药剂来补益。服药后反而觉得更加烦闷难受，神识昏迷不知人事。天气炎热蒸腾，要下雨才能缓解。瘴病的热象蒸腾，要出汗才能解除。白术止汗，黄芪止汗，使腠理密闭，汗液无法排出，热象蒸腾没有途径得以解除，反而加重烦闷和神志昏迷，所以白术和黄芪也不宜急于使用。有人问：白术和黄芪，它们的性质是收敛止汗，所以不可用；而肉桂也不是发汗药，为什么又用它呢？我说：肉桂固然能止汗，本草记载说它主治温中，又说“本乎地者亲下”，补肾用肉桂，所以它的性质也能引导上焦的阳气下达肾经，所以可以使用。有人问：您说天气热蒸，得雨才解；瘴病热蒸，得汗才除。现在病人自汗，按理说瘴病应该痊愈了，为什么还是没有解除？我说：这种自汗只是暂时得到片刻的热闷舒缓罢了。如果想要痊愈，必须温中固下，调和正气，使阴升阳降，荣卫调和，邪气无处容身，自然会大汗如雨，从头到脚，无处不出。大汗之后浑身冰冷，只有口中呼出的气体略微温暖。如果没有见到这种证候，瘴热就不会再复发。这个时候只应当谨慎调摄，经过一百天，元气可以恢复常态。
Zhang (miasma malaria) and Nue (ague/malaria) appear similar but are fundamentally different. Therefore, mild cases of Zhang closely resemble Nue. If physicians are unaware of the treatment principles for Zhang and indiscriminately employ Changshan (Dichroa Root), Bai Pi (White Arsenic), and Caoguo (Black Cardamom) to induce vomiting and expel phlegm, it will cause those with sufficient Yuan Qi (primordial qi) to suffer from lingering discomfort, while those with deficient Yuan Qi will immediately develop edema, often leading to death. This is deeply lamentable. The reason is that Zhang disease arises from the failure of Yang Qi to descend; inducing vomiting further causes this non-descending Yang Qi to rise excessively and weakens the Middle Qi (Spleen/Stomach qi). Cases that do not become critical are extremely rare. Thus, Bai Pi and Caoguo must absolutely not be used. However, Changshan still has its utility; its potency can remove miasma qi from the skin and pores, as well as pathogenic factors causing chills and fever, which typically reside in the Ying-Wei (Nutritive-Defensive) system and between the muscles. To eradicate the root cause, Changshan is indispensable. Yet, Changshan frequently induces vomiting; it must be processed to prevent emesis before use. It can be taken cold with Qibao Yin (Seven Treasures Decoction) or Jiemie Wan (Malaria-Cutting Pill), administered six to seven times daily with wine, which also prevents vomiting. These are proven effective remedies. One must understand that such drugs serve as a last resort ("the rear guard"). When Zhang first manifests, one must first harmonize the Zheng Qi (righteous qi), warm the Middle and anchor the Lower, and secure the patient's Yuan Qi. This corresponds to the military strategy of "avoiding the enemy's sharpness when they first arrive." During the intermittent phase of fever, when it is clear that the pattern follows a rhythm—occurring once daily for five to six hours before subsiding, or every other day—and upon confirming that the Spleen and Stomach have harmonized, damp-cold in the Lower Jiao (Triple Burner) has dissipated, and Yuan Qi is gradually recovering while pathogenic heat diminishes, then Qibao Yin or Jiemie Wan should be administered, resulting in a swift cure. This aligns with the strategy of "striking the enemy when they are weary and retreating." If this principle is not understood, using Changshan during the peak of intense heat will not only be ineffective but will further damage the Zheng Qi.
The onset of Zhang disease is generally due to summer-heat, causing loose Cou Li (skin pores and interstices) and spontaneous sweating. Physicians, observing this spontaneous sweating, treat it according to Nue protocols, using tonifying formulas containing Renshen (Ginseng), Danggui (Angelica Sinensis), Baizhu (Atractylodes Macrocephala), etc. After ingestion, patients feel increasingly restless and uncomfortable, becoming delirious and unconscious. Just as sultry weather requires rain to bring relief, the steaming heat of Zhang disease requires sweating to dissipate. Baizhu stops sweating, Huangqi (Astragalus) stops sweating, and they tighten the Cou Li, preventing sweat from exiting. Consequently, the steaming heat has no outlet to resolve, exacerbating restlessness and coma. Therefore, Baizhu and Huangqi should not be hastily employed. Some ask: Since Baizhu and Huangqi have astringent properties to stop sweating, they are unusable; yet Rougui (Cinnamon Bark) is also not a diaphoretic herb, why is it used? I reply: Although Rougui can stop sweating, Materia Medica states it warms the Middle and, being rooted in the earth, tends downward. It is used to tonify the Kidney; thus, its nature can guide Yang Qi from the Upper Jiao down to the Kidney Meridian, making it usable. Others ask: You stated that sultry weather resolves with rain, and Zhang heat resolves with sweat. Since the patient is sweating spontaneously, shouldn't the Zhang disease be resolving? Why does it persist? I answer: This spontaneous sweating only provides momentary relief from heat and oppression. For true resolution, one must warm the Middle and consolidate the Lower, harmonize the Zheng Qi, ensure Yin rises and Yang descends, and harmonize Ying and Wei so that pathogens have no place to lodge. Naturally, profuse sweating like rain will occur, covering the head to toe. After this profuse sweating, the body becomes ice-cold, with only the breath from the mouth remaining slightly warm. If these signs do not appear, the Zhang heat will not recur. At this stage, careful nursing is essential; after one hundred days, the Yuan Qi can return to normal.