少阳胆为风木之府，疟家寒热之邪，必归少阳，是以疟脉多弦。少阳居半表半里之间，
其气从阳则热，从阴则寒也。疟者金火交诊，故其病寒热并作也。
气分受邪，发于六阳时；血分受邪，发于六阴时。浅者每日一发，深者间日一发，极深
者三
日发也。浅者属阳，阳性易动，故日行之气，触着便发。深者属阴，阴性常静，故日行之气
，屡触而始发也。
疟发时，虽大热大渴，必以淡生姜汤适寒温饮之。若恣饮冷水瓜果，脾胃转伤，邪气不
达，绵延难愈。
凡疟疾多热，久而不解者，其人必本阴虚，法当益阴除热，非当归、鳖甲、制首乌、牛
膝之
属，不能除也。多寒而久不解者，其人必本阳虚，法当甘温散邪，非干姜、附子、桂枝、人
参之属，不能已也。
疟邪在阳者，其证多汗，感而即发，邪不能留。其留藏不去者，惟阴邪耳，阴邪不能作
汗
，虽以汗药发之亦不得，惟甘润和阴，如当归、牛膝之属，多服久服，自能出汗而解也。
伤寒往来寒热，劳瘵寒热如疟，伤食劳役，香港脚疝气，肿毒初起，俱有寒热。阴虚证，
每日
午后发热恶寒，至晚亦得微汗而解。脉弦而数，但不大弦为辨耳，俱不可误认为疟也。凡病
寒热，有期者疟也，无期者诸病也。
凡疟病自阴而渐阳，自迟而渐早者，由重而轻也。自早而渐迟，自阳而渐阴者，由轻而
重也
。凡感邪极深，发愈晏而作愈迟者，必使渐早渐近，方是佳兆。故治此疾者，春夏为易，秋
冬为难。
疟邪必从汗出，邪在阴者，必汗出至足乃佳，然非麻、葛辈可发，但开郁通经，其邪热
即散，而为汗矣。其虚者，非参、 、归、地，则终不能得汗也。
古称风寒暑湿，皆能成疟，然必客于营卫之舍，然后成疟，不尔不成疟也。夫营之有舍
，犹
行人之有传舍也。营卫之气，日行一周，历五脏六腑、十二经络之界分，必其舍有邪，与日
行之卫气相遇则病作；离则病休，故发作有时，与伤寒大异也。
俗有伤寒变疟、疟变伤寒之说，愚谓伤寒变疟者，本是疟邪，因其气特甚，故一发而不
止，
迨汗出气衰，乃复返于舍而后日作，非伤寒能变疟也。疟变伤寒者，本是伤寒，因邪气先中
少阳，故寒热如疟，其邪递引递出，遍满三阳之界，因而发热不止，设不解，则又转而之三
阴，非疟邪能变伤寒也。是以始先似疟之证，热虽退，身表尚有余热，不似疟之热退即凉也
。始先似伤寒者，汗常浃体而热不退，过一二日，忽振寒而发热，或热退一日而复作寒热，
非如伤寒之汗出即热退而邪解也。学人智识既具，自当独断，岂可习焉不察，自同众人也。
久疟不退，邪气陷入阴分，亏损营血，有热无寒，口燥唇干，有似伤寒，人皆谓之变伤
寒，不知其为传劳瘵也，脉将散大，或细数，而死期至矣。
少阳胆是风木之气所主的脏腑，患疟疾者感受的寒热邪气，必然归于少阳经，所以疟疾的脉象多呈弦脉。少阳经位于半表半里之间，其气若偏向阳分则表现为热，偏向阴分则表现为寒。疟疾是金（燥）与火（热）相互交争所致，因此病症表现为寒热交替发作。
邪气侵犯气分，发病时间多在六阳时（白天阳气盛之时）；邪气侵犯血分，发病时间多在六阴时（夜间阴气盛之时）。病位浅的，每天发作一次；病位深的，隔天发作一次；病位极深的，三天发作一次。病位浅的属于阳证，阳气的特性是容易变动，所以随着日行卫气的运行，一旦触动邪气就会立即发作。病位深的属于阴证，阴气的特性是常静，所以日行的卫气多次触动邪气后才会发作。
疟疾发作时，即使出现高热、大渴的症状，也必须用淡生姜汤，在温度适宜时饮用。如果放纵地饮用冷水或生冷瓜果，会导致脾胃受损，邪气无法透达外出，病情就会拖延难愈。
凡是疟疾多表现为热证，但长久不愈的，此人必定原本阴虚，治疗法则应当滋阴清热，如果不是使用当归、鳖甲、制何首乌、牛膝这类药物，是不能清除虚热的。多表现为寒证且长久不愈的，此人必定原本阳虚，治疗法则应当用甘温之药发散邪气，如果不是使用干姜、附子、桂枝、人参这类药物，是不能止住寒证的。
疟邪在阳分的，症状多汗出，感邪后立即发作，邪气不能久留。那些留滞藏伏不去的，只有阴邪罢了，阴邪不能通过发汗排出，即使使用发汗药也无法使其出汗，只有使用甘润和阴的药物，如当归、牛膝之类，长期服用，自然能出汗而病解。
伤寒症见往来寒热，劳瘵（肺结核等慢性消耗性疾病）寒热如疟，伤食或过度劳累，脚气病及疝气，肿毒初起阶段，都可能出现寒热症状。阴虚证患者，每日午后发热恶寒，到了晚上微微出汗后得以缓解。脉象弦而数，只要不是特别弦硬即可辨别，这些情况都不可以误认为是疟疾。凡是寒热症状有固定发作时间的，是疟疾；没有固定发作时间的，是其他疾病。
凡是疟病从阴分逐渐转向阳分，从发作时间晚逐渐变早的，是由重转轻的好现象。从发作时间早逐渐变晚，从阳分逐渐转向阴分的，是由轻转重的坏现象。凡是感受邪气极深，发作越晚、开始发作的时间越迟的，必须使发作时间逐渐提前、接近正常节律，这才是佳兆。所以治疗这种病，春夏季节比较容易，秋冬季节比较困难。
疟邪必须通过汗出而解，邪气在阴分的，必须出汗直到足部才好，但这不能用麻黄、葛根这类强力发汗药来发汗，只需开郁结、通经络，邪热自然消散，随之而出汗。对于体虚的患者，如果不使用人参、黄芪、当归、地黄这类补益药，终究无法得出汗来。
古人称风寒暑湿都能导致疟疾，但邪气必须客居于营卫之舍（营卫运行的居所/间隙），然后才能形成疟疾，否则不会形成疟疾。营气有它的居所，就像行人有驿站一样。营卫之气，每天循环运行一周，经过五脏六腑、十二经络的分界区域，一定是其居所中有邪气，与每日运行的卫气相遇时疾病发作；离开时疾病休止，所以发作有定时，这与伤寒大不相同。
世俗有“伤寒变成疟疾”、“疟疾变成伤寒”的说法，我认为所谓“伤寒变疟”，本来是疟邪，因为邪气特别强盛，所以一发而不停止，等到汗出气衰之后，才又返回到居所中从而每日发作，并不是伤寒能变成疟疾。所谓“疟变伤寒”，本来是伤寒，因为邪气先侵袭少阳经，所以寒热像疟疾一样，邪气依次牵引、依次外出，遍布三阳经的分界区域，因而发热不止，如果不解除，又会转而进入三阴经，并不是疟邪能变成伤寒。所以起初类似疟疾的证候，热虽然退了，体表还有余热，不像疟疾那样热退即凉。起初类似伤寒的证候，常常全身大汗但热不退，过一两天，突然恶寒发热，或者热退一天后又出现寒热，不像伤寒那样汗出即热退邪解。学者智慧见识既已具备，自然应当独立判断，怎么能习以为常而不加考察，自同于普通人呢？
久疟不退，邪气陷入阴分，亏损营血，表现为有热无寒，口燥唇干，看起来像伤寒，人们都称之为“变伤寒”，却不知道这是传变为劳瘵（慢性消耗性疾病），脉象将变得散大，或者细数，这时死期就到了。
The Shaoyang Gallbladder is the residence of Wind-Wood Qi. The pathogenic cold and heat of malaria must return to the Shaoyang channel, hence the pulse in malaria is often wiry (Xian). Shaoyang resides between the exterior and interior; its Qi manifests as heat when it moves toward Yang, and as cold when it moves toward Yin. Malaria is caused by the interaction of Metal (Dryness) and Fire (Heat), thus the disease presents with alternating chills and fever.
When the pathogen affects the Qi level, onset occurs during the Six Yang hours (daytime); when it affects the Blood level, onset occurs during the Six Yin hours (nighttime). When shallow, it attacks once daily; when deep, it attacks every other day; when extremely deep, it attacks every three days. Shallow cases belong to Yang; Yang Qi is easily agitated, so when the daily circulating Wei Qi touches the pathogen, it triggers immediate onset. Deep cases belong to Yin; Yin Qi is naturally quiet, so the daily circulating Wei Qi must touch the pathogen repeatedly before onset occurs.
During a malaria attack, even if there is high fever and intense thirst, one must drink light ginger soup at a lukewarm temperature. If one indulges in drinking cold water or raw fruits and vegetables, the Spleen and Stomach will be further damaged, the pathogen will fail to be expelled, and the condition will become chronic and difficult to cure.
In cases where malaria is predominantly heat-related and persists for a long time without resolution, the patient inherently suffers from Yin deficiency. The treatment principle should be to nourish Yin and clear heat. Without herbs such as Dang Gui (Angelicae Sinensis Radix), Bie Jia (Testudinis Carapax et Plastrum), Zhi He Shou Wu (Polygoni Multiflori Preparati Radix), and Niu Xi (Achyranthis Bidentatae Radix), the heat cannot be cleared. In cases where malaria is predominantly cold-related and persists without resolution, the patient inherently suffers from Yang deficiency. The treatment principle should be to use sweet-warm herbs to disperse the pathogen. Without herbs such as Gan Jiang (Zingiberis Rhizoma), Fu Zi (Aconiti Lateralis Radix Praeparata), Gui Zhi (Cinnamomi Ramulus), and Ren Shen (Ginseng Radix et Rhizoma), the cold cannot cease.
When the malaria pathogen is in the Yang aspect, symptoms often include sweating; upon contraction, it attacks immediately, and the pathogen cannot remain. Those that linger and do not depart are exclusively Yin pathogens. Yin pathogens cannot induce sweating; even if diaphoretic agents are used, sweat cannot be produced. Only by using sweet-moistening herbs to harmonize Yin, such as Dang Gui and Niu Xi, taken frequently and over a long period, can sweat naturally occur, leading to resolution.
Shanghan (Cold Damage) presenting with alternating chills and fever, Lao Zhai (consumptive disease like tuberculosis) presenting with chills and fever resembling malaria, food stagnation, overwork, Hong Jiao (gout/foot disease), and hernia, as well as the initial stage of swelling and toxicity, all may present with chills and fever. In Yin deficiency patterns, patients experience fever and aversion to cold every afternoon after noon, resolving with slight sweating late at night. The pulse is wiry and rapid, but distinguished by not being excessively wiry. None of these should be mistaken for malaria. Generally, chills and fever with periodicity indicate malaria; those without periodicity indicate other diseases.
When a malaria disease progresses from Yin to Yang, and from delayed onset to earlier onset, it indicates a transition from severe to mild. When it progresses from early onset to delayed onset, and from Yang to Yin, it indicates a transition from mild to severe. When the contracted pathogen is extremely deep, causing later and later onset times, the favorable sign is for the onset to gradually advance and approach normal rhythm. Therefore, treating this disease is easier in Spring and Summer, and more difficult in Autumn and Winter.
The malaria pathogen must exit through sweating. When the pathogen is in the Yin aspect, sweating reaching the feet is ideal. However, this cannot be achieved with strong diaphoretics like Ma Huang (Ephedrae Herba) or Ge Gen (Puerariae Lobatae Radix). Instead, by opening depression and unblocking meridians, the pathogenic heat will dissipate, resulting in sweating. For deficient patients, unless Ginseng, Huang Qi (Astragali Radix), Dang Gui, and Di Huang (Rehmanniae Radix) are used, sweat ultimately cannot be produced.
Ancient texts state that Wind, Cold, Summer-heat, and Dampness can all cause malaria, but the pathogen must lodge in the "residences" of Ying and Wei Qi to form malaria; otherwise, it does not. The residence of Ying Qi is like a relay station for travelers. Ying and Wei Qi circulate once daily throughout the boundaries of the Five Zang, Six Fu organs, and Twelve Meridians. Disease arises when the pathogen in the residence encounters the daily circulating Wei Qi; it rests when they separate. Hence, the attacks have fixed timing, which differs significantly from Shanghan.
Popular theory suggests "Shanghan transforming into malaria" and "malaria transforming into Shanghan." I argue that what is called "Shanghan transforming into malaria" is originally a malaria pathogen. Because the pathogen was exceptionally strong, it attacked continuously until Qi declined after sweating, then returned to its residence to attack daily; it is not Shanghan transforming into malaria. What is called "malaria transforming into Shanghan" is originally Shanghan. Because the pathogen first invaded the Shaoyang channel, chills and fever resembled malaria. The pathogen sequentially moved outward, filling the boundaries of the Three Yang channels, causing continuous fever. If unresolved, it would turn to the Three Yin channels; it is not malaria pathogen transforming into Shanghan. Thus, initially Shanghan-like syndromes may have residual heat on the body surface even after fever subsides, unlike malaria where cooling follows fever reduction. Initially malaria-like syndromes often feature profuse sweating without fever reduction; after one or two days, sudden chills and fever may occur, or fever may subside for a day before recurring. This differs from Shanghan, where sweating leads to immediate fever reduction and pathogen resolution. Scholars with wisdom and insight should make independent judgments; how can they accept things as they are without scrutiny, assimilating themselves to the masses?
In prolonged malaria that does not resolve, the pathogen sinks into the Yin aspect, depleting Ying and Blood. Symptoms include fever without chills, dry mouth and lips, resembling Shanghan. People call this "transforming into Shanghan," unaware that it is transmitting into Lao Zhai (consumptive disease). When the pulse becomes scattered and large, or fine and rapid, the time of death has arrived.