旧传出岭之后，复有回头瘴者。大概与在广而发瘴，及方入广而不伏水土者不异。盖南
方阳气常泄，阴气常盛，二气相搏，四时悉有寒热之气，人感之，即作寒热之病。寒则战栗
，热则怫郁，多由得汗而解，此广瘴之寒热也。今所谓回头瘴，及方入广而不伏水土者，亦
不过阴阳相搏，气候不调而感疾耳。岭南天气，冬无霜雪，春寒，秋热，气候不齐，或一日而
忽然更变，与方外天气大不相侔。今回头瘴者，盖是先受广中之气，复感外方之气，冷热相
忤，寒暄不调，遂作阴阳相搏之疾，须度时候之寒热，量元气之浓薄。如出岭于孟冬时者，
广尚多暄而少寒，或转北风，或有暴冷。若届途之际，宜服和解散、神术散之类，和脾胃以
逐风邪。及至外方，则天寒地冻，将及境之际，可服正气散、人参养胃汤之类。绝旧瘴以御
时寒可也。然此四药，亦特筌蹄耳，其实在保躬调养，酌序消详，切不可以得出瘴地而恣欲
，此病之所由作也。故所谓回头瘴者，岂虚语哉。
继洪曰∶予寓岭南既久，愈知瘴疾不易用药。若病患身热而复寒，谓之冷瘴，不换金正
气散主之。若身热胸痞，或呕，或噎，大便不利者，嘉禾散。若病轻而觉有食积，兼用些少
感应丸，无积者，不可用。若病重者，不可妄用。转利，惟当温中固下。若冬末春初，因寒
而作大热者，小柴胡汤。夏月因暑气者，六和汤。若身极热，而头极痛，脉数者，为热瘴，
宜用南人挑草子法，亦不可不服药。第此证病深，最为难治。盖凉药多不可用，惟宜热药，
须得法以用之，如附子汤冷服者，是也。然此非工巧以处之则不可。如身热汗不多，头痛未
解，或且与和解散。如腰以上极热，腰以下稍凉，胸膈烦渴，腰腿重疼，或大便溏滑，其脉
数而按之不实，此阳浮阴闭也。惟李待诏生姜附子汤最妙。凡初病者，以生姜附子能发散耳
。若病经去汗既多，虚烦潮上，则惟恐其不敛不降，宜用熟附、干姜、沉香而冷服之。若便
利，则不必沉香。如烦甚，则少加竹茹。渴甚，多加人参、北五味。咳逆加丁香、淡竹叶。
若烦躁而有异象，眩惑，夜不安寝，可略与温胆汤。惟大便利者，不可服。若烦渴大作，宜
夺命散，或用冷汤，倍加人参、附子。若烦热，大便自利，或小便不涩，不可以赤为热，或
膝胫以下稍凉，此乃病邪所激，气血俱虚，表热无以养中，故水热而内虚也。可急服姜附汤
之类，及灸气海、足三里。若至四肢厥冷，两足冷甚，头额虚汗，或时咳逆，脉数而促，其
证多危，惟以三建汤之属，能敛心液，能壮真阳，可以更生也。又有哑瘴，即热瘴之甚者。
医书谓血得寒则凝泣，得热则淖溢。故热瘴面赤，心热，舌破，鼻衄，皆瘴热沸其血上涌所
致，故宜用挑草子法。甚则血上塞其心窍，故昏不能言，或但噫噫作声，即哑瘴也。治此者
，当散其血，用《局方》黑神散，立见神效。其或涎迷心窍而舌强者亦有之，却非真哑瘴也
，及兼风痰之证者，俱当审察而后用治。（本论有无稽之方，俱削去不录）
旧时传说，从岭南地区返回后，还会再次发作“回头瘴”。这大概与在广西当地发作的瘴气病，以及刚进入广西地区因不适应水土而引发的疾病没有区别。因为南方阳气容易耗散，阴气往往旺盛，阴阳二气相互搏结，四季都有寒热交替的气候特征，人若感受这种邪气，就会引发寒热往来的病症。感到寒冷时会战栗发抖，感到发热时则郁闭烦闷，大多通过出汗而痊愈，这就是广地瘴气的寒热表现。如今所说的“回头瘴”，以及刚入广西因水土不服而生病的情况，也不过是阴阳相搏、气候不调而导致的疾病罢了。
岭南地区的天气，冬天没有霜雪，春天寒冷，秋天炎热，气候不恒定，有时一天之内突然变化，这与外地的气候大不相同。所谓的“回头瘴”，大概是先感染了岭南地区的气候邪气，又感受了外地的风寒之气，冷热相互冲突，寒暖不调，于是形成了阴阳相搏的疾病。必须根据时令的寒热变化，衡量人体元气的强弱浓薄来治疗。例如在农历十月（孟冬）出岭的人，岭南地区尚且温暖多暖少寒，或者刮起北风，出现骤然变冷的情况。如果在旅途中，适宜服用和解散、神术散之类的方剂，以调和脾胃、驱除风邪。等到进入外地，天气寒冷大地结冰，即将到达目的地时，可以服用正气散、人参养胃汤之类的方剂。这样可以杜绝旧有的瘴气并抵御当时的寒气。然而这四类药物，也只是渡河的筏子（比喻手段），真正关键在于保养身体、调养气息，斟酌次序详细分析，切不可认为出了瘴气之地就放纵欲望，这是导致疾病产生的原因。所以所谓的“回头瘴”，难道是空话吗？
继洪说：我寓居岭南已久，越发知道治疗瘴疾不容易用药。如果病人身体发热却又怕冷，称为“冷瘴”，主用不换金正气散。如果身体发热且胸中痞闷，或者呕吐，或者噎膈，大便不通利的，用嘉禾散。如果病情轻浅且感觉有食积，兼用少量感应丸，如果没有积滞的，不可使用。如果病情严重，不可妄用。如果出现腹泻转利，只应当温补中焦、固涩下焦。如果是冬末春初，因受寒而引发高热，用小柴胡汤。夏季因暑气引发的，用六和汤。如果身体极度发热，头部剧烈疼痛，脉搏快速，称为“热瘴”，适宜采用南方人的“挑草子”疗法，但也不可不服药。只是此证病位深，最为难治。因为凉性药物大多不可用，只宜用热性药物，必须讲究方法使用，比如将附子汤放冷后服用，就是这样的方法。然而这不是医术精巧的大夫来处理是不行的。如果身体发热但汗出不多，头痛未解，或许可以先给予和解散。如果腰部以上极热，腰部以下稍凉，胸膈烦渴，腰腿沉重疼痛，或者大便稀溏滑泄，脉象数而按之不实，这是阳浮于上、阴闭于下的证候。只有李待诏的生姜附子汤最为巧妙。凡是初发病者，是因为生姜、附子能发散邪气。如果病程经过发汗之后大汗淋漓，出现虚烦热气上冲，则恐怕其不能收敛下降，适宜用熟附子、干姜、沉香并冷服。如果大便通畅，则不必用沉香。如果烦躁严重，则少加竹茹。口渴严重，多加人参、北五味子。咳嗽气逆加丁香、淡竹叶。如果烦躁且有异常征象，眩晕迷惑，夜间不能安睡，可略予温胆汤。但是大便完全通利者，不可服用。如果烦渴大作，宜用夺命散，或者用冷汤送服，加倍加入人参、附子。如果烦热，大便自利，或者小便不涩滞，不可以尿赤为热证，或者膝盖小腿以下稍凉，这是病邪激发所致，气血俱虚，表热无法滋养中焦，所以水液偏热而内部虚弱。可急服姜附汤之类，并灸气海穴、足三里穴。如果发展到四肢厥冷，两脚特别冷，额头出虚汗，或者时而咳嗽气逆，脉象数而急促，这种证候多属危重，只有三建汤这类方剂，能够收敛心液，能够壮旺真阳，可以使患者起死回生。又有“哑瘴”，即热瘴中严重的类型。医书说血液遇到寒则凝滞，遇到热则流动溢出。所以热瘴患者面红，心中发热，舌头破裂，鼻出血，都是瘴热沸腾血液向上涌溢所致，所以适宜用挑草子法。严重时血液上塞心窍，导致昏迷不能说话，或者只是发出呜呜的声音，这就是哑瘴。治疗这种情况，应当消散瘀血，使用《局方》中的黑神散，立刻可见神奇疗效。其中也有因痰涎迷蔽心窍而导致舌强不语的，但这并非真正的哑瘴，以及兼有风痰证候的，都应当仔细审察后再进行治疗。（本论中有无根据的方剂，都已删去不录）
It was said in old texts that after returning from Lingnan, one might suffer from "returning miasma" (Huitou Zhang). This is generally no different from miasma contracted while in Guangxi or from acclimatization issues upon first entering Guangxi. In the south, Yang Qi tends to dissipate while Yin Qi is often abundant. The struggle between these two energies results in cold and heat fluctuations throughout all four seasons. When humans are affected by this, they develop diseases characterized by alternating chills and fever. Chills manifest as shivering, while fever presents as stifling oppression. Recovery usually occurs through sweating; this constitutes the chills and fever pattern of Guangxi miasma. The so-called "returning miasma" and illnesses arising from initial acclimatization difficulties in Guangxi are merely diseases caused by the struggle of Yin and Yang and climatic disharmony.
The climate in Lingnan features no frost or snow in winter, cold springs, and hot autumns, with inconsistent weather conditions that can change suddenly within a single day, differing greatly from climates elsewhere. "Returning miasma" typically arises when one has first been affected by the miasmic qi of Guangxi and subsequently exposed to external climatic factors. The conflict between cold and heat, and the imbalance of warmth and chill, lead to a disease of Yin-Yang struggle. Treatment must consider the seasonal temperature variations and assess the thickness and strength of the patient's Yuan Qi (Original Qi). For instance, those leaving Guangxi in the first month of winter find it still warm with little cold, though northerly winds may bring sudden chill. During travel, formulas such as Hejie San (Harmonizing Powder) or Shenzhu San (Divine Efficacy Powder) should be taken to harmonize the Spleen and Stomach and expel Wind pathogenic factors. Upon entering colder regions where the ground freezes, near the destination, Zhengqi San (Righteous Qi Powder) or Renshen Yangwei Tang (Ginseng Stomach-Nourishing Decoction) may be used to prevent old miasma and resist the current cold. However, these four types of medicines are merely means to an end (like a fish trap); the true key lies in self-care and regulation. One must carefully evaluate the situation and must not indulge desires upon leaving the miasma area, as this is the cause of such illnesses. Thus, the concept of "returning miasma" is not empty talk.
Ji Hong stated: Having resided in Lingnan for a long time, I have come to realize that treating miasma diseases requires careful selection of medications. If a patient exhibits fever accompanied by chills, it is called "Cold Miasma" (Leng Zhang), primarily treated with Buhuanjin Zhengqi San (Non-Exchanging Metal Righteous Qi Powder). If there is fever with chest fullness, vomiting, or dysphagia, along with constipation, Jiahe San (Abundant Grain Powder) is indicated. If the illness is mild and food stagnation is suspected, a small amount of Yinggan Wan (Responsive Pill) may be added; if there is no stagnation, it should not be used. In severe cases, do not use it recklessly. If diarrhea ensues, only warming the Middle and securing the Lower Jiao is appropriate. In late winter or early spring, if high fever is triggered by cold, Xiao Chaihu Tang (Minor Bupleurum Decoction) is used. In summer, if caused by summerheat, Liuhe Tang (Six Harmonies Decoction) is applied. If the body is extremely hot, the head suffers severe pain, and the pulse is rapid, it is termed "Hot Miasma" (Re Zhang). The southern method of "picking grass seeds" (Tiaocaozi Fa, likely a local therapeutic technique) is suitable, but medication cannot be omitted. This condition is deep-seated and difficult to treat. Cold-natured herbs are mostly contraindicated; only hot-natured herbs should be used, employing specific methods, such as taking Fuzi Tang (Aconite Decoction) when cooled. This requires skilled medical judgment. If fever persists with scant sweating and unresolved headache, Hejie San might be considered initially. If the upper body is extremely hot while the lower body is slightly cool, accompanied by chest/epigastric irritability and thirst, heavy/painful waist and legs, loose stools, and a rapid pulse that feels empty upon pressure, this indicates Floating Yang and Closed Yin. Li Daizhao’s Shengjiang Fuzi Tang (Fresh Ginger and Aconite Decoction) is most excellent. For initial onset, Fresh Ginger and Aconite help disperse pathogens. However, after excessive sweating leading to deficiency, vexation, and rising heat, one fears failure to consolidate and descend; thus, Prepared Aconite (Shu Fuzi), Dried Ginger (Gan Jiang), and Agarwood (Chen Xiang) should be taken cold. If bowel movements are free, Agarwood is unnecessary. For severe vexation, add Bamboo Shavings (Zhuru). For extreme thirst, increase Ginseng (Renshen) and Schisandra (Bei Wuwei Zi). For cough and rebellious Qi, add Clove (Dingxiang) and Light Bamboo Leaves (Dan Zhuye). If vexation is accompanied by abnormal signs, dizziness, confusion, and insomnia, Wendan Tang (Warm Gallbladder Decoction) may be given lightly, but it is contraindicated in cases of profuse diarrhea. For severe vexation and thirst, Duoming San (Life-Snatching Powder) or cold water with doubled Ginseng and Aconite is indicated. If there is vexatious heat, spontaneous diarrhea, or non-obstructed urination, red urine should not necessarily be interpreted as heat, especially if the knees and calves are slightly cool. This results from pathogenic stimulation causing Qi and Blood deficiency, where exterior heat fails to nourish the interior, leading to internal heat and deficiency. Immediately administer Jiangfu Tang (Ginger and Aconite Decoction) and moxa Qihai (CV6) and Zusanli (ST36). If progressing to cold limbs, extreme cold in both feet, deficient sweat on the forehead, occasional cough/rebellious Qi, and a rapid, intermittent pulse, the prognosis is critical. Only Sanjian Tang (Three Establishments Decoction) type formulas can consolidate Heart fluids and strengthen True Yang, potentially restoring life.
There is also "Mute Miasma" (Ya Zhang), which is a severe form of Hot Miasma. Medical texts state that blood coagulates in cold and flows freely in heat. Therefore, in Hot Miasma, facial redness, heart heat, tongue fissures, and epistaxis are caused by miasmic heat boiling blood upward. The "picking grass seeds" method is suitable. In severe cases, blood obstructs the Heart orifices, causing coma and inability to speak, or only producing groaning sounds; this is Mute Miasma. Treatment should resolve blood stasis using Heishen San (Black Divine Powder) from *Ju Fang*, which yields miraculous effects. Some cases involve phlegm misting the Heart orifices causing tongue stiffness, but this is not true Mute Miasma. Cases involving Wind-Phlegm must be carefully examined before treatment. (Unsubstantiated prescriptions in this treatise have been deleted.)