（《素问·至真要大论》）
帝曰∶火热复恶寒发热，如有疟状，或一日发，或间数日发，其故何也？（凡病寒热，多由外感，然有不因风寒而
火热内盛者，亦为恶寒发热，其作有期，状虽似疟而实非疟证，故特为问辨也。）岐伯曰∶胜复之气，会遇之时，有多少
也。阴气多而阳气少，则其发日远；阳气多而阴气少，则其发日近。此胜复相搏，盛衰之节，疟亦同法。（夫寒热者，阴
阳之气也。迟速者，阴阳之性也。人之阴阳则水火也，营卫也。有热而反寒者，火极似水也。寒而反热者，阴极似阳也。
阴阳和则血气匀，表里治；阴阳不和，则胜复之气，会遇之时，各有多少矣。故阳入之阴，则阴不胜阳而为热；阴出之
阳，则阳不胜阴而为寒。又若阴多阳少，则阴性缓而会遇迟，故其发日远；阳多阴少，则阳性速而会遇早，故其发日近。
此胜复盛衰之节，虽非疟证，而多变似疟，法亦同然。所谓同者，皆阴阳出入之理也。然同中自有不同，则曰是疟，曰
非疟。是疟非疟者，在有邪无邪之辨耳。真疟有邪，由卫气之会以为止作；似疟无邪，由水火争胜以为盛衰，此则一责
在表，一责在里，一治在邪，一治在正，勿谓法同而治亦同也。同与不同之间，即杀人生人之岐也，学人于此，不可不
察。）
黄帝问道：火热之邪再次引发恶寒发热，症状如同疟疾一般，有时每天发作，有时间隔数日才发作，这是什么缘故呢？（凡是出现寒热往来的病症，大多由外感引起，但也有并非因风寒所致，而是火热内盛引起的，同样会出现恶寒发热，且发作有定时，虽然症状类似疟疾，但实质上不是疟疾，所以特意提出疑问进行辨析。）
岐伯回答说：胜气与复气相遇的时候，其力量的强弱是有差异的。如果阴气多而阳气少，那么发作的时间间隔就远；如果阳气多而阴气少，那么发作的时间间隔就近。这是胜气与复气相互搏结，盛衰交替的规律，疟疾也遵循同样的法则。（所谓寒热，是阴阳之气的表现。发作快慢，是阴阳性质的体现。人体的阴阳对应着水火，也对应着营气和卫气。有热象却反而感到寒冷，是因为火极似水；有寒象却反而感到发热，是因为阴极似阳。阴阳调和则气血均匀，表里协调；阴阳不和，则胜气与复气相遇时，各自的力量多少不同。因此，当阳气进入阴分，阴不能制约阳，就会表现为发热；当阴气出于阳分，阳不能制约阴，就会表现为发冷。再者，如果阴多阳少，阴的性质迟缓，相遇的时间就晚，所以发作间隔时间长；如果阳多阴少，阳的性质迅速，相遇的时间就早，所以发作间隔时间短。这种胜复盛衰的节律，虽然不一定是疟疾，但很多情况类似疟疾，其原理也是相同的。所说的相同之处，都是基于阴阳出入的道理。然而相同之中又有不同，这就区分了是疟疾还是非疟疾。判断是疟或非疟的关键，在于辨别体内是否有邪气。真正的疟疾有邪气，由卫气的会合来决定停止和发作；类似疟疾而无邪气，由水火之气的争胜来决定盛衰。前者病位在表，后者病位在里；前者治疗针对邪气，后者治疗针对正气，不要认为原理相同，治疗方法也就相同。同与不同之间的细微差别，就是决定生死的关键所在，学习中医的人对此不可不仔细考察。）
The Yellow Emperor asked: When pathogenic fire and heat reappear, causing aversion to cold and fever, resembling malaria, sometimes occurring daily or every few days, what is the reason for this? (Generally, alternating chills and fever are mostly caused by external contraction. However, there are cases not due to wind-cold, but rather excessive internal fire-heat, which also present with chills and fever. These episodes have a specific timing. Although the symptoms resemble malaria, they are essentially not malaria; thus, this question is raised for clarification.)
Qibo replied: The time of encounter between the victorious qi (Sheng) and the retaliatory qi (Fu) varies in intensity. If yin qi is abundant and yang qi is scarce, the interval between episodes is long; if yang qi is abundant and yin qi is scarce, the interval between episodes is short. This reflects the rhythm of victory and retaliation, and the fluctuation of excess and deficiency. Malaria follows the same principle. (Chills and fever represent the dynamics of yin and yang qi. The speed of onset reflects the nature of yin and yang. In the human body, yin and yang correspond to water and fire, as well as Ying (Nutrient) Qi and Wei (Defensive) Qi. A sensation of cold despite heat indicates extreme fire mimicking water; a sensation of heat despite cold indicates extreme yin mimicking yang. When yin and yang are harmonious, blood and qi are balanced, and the interior and exterior are regulated. When yin and yang are disharmonious, the encounter of Sheng and Fu qi involves varying degrees of abundance and scarcity. Thus, when yang enters yin, yin fails to control yang, resulting in heat; when yin emerges from yang, yang fails to control yin, resulting in cold. Furthermore, if yin is abundant and yang is scarce, the sluggish nature of yin delays their encounter, leading to longer intervals between episodes. If yang is abundant and yin is scarce, the rapid nature of yang accelerates their encounter, leading to shorter intervals. This rhythm of Sheng and Fu, though not necessarily malaria, often presents similarly, governed by the same logic of yin-yang entry and exit. The similarity lies in the principles of yin-yang movement. However, differences exist within these similarities, distinguishing true malaria from malaria-like conditions. The key distinction lies in the presence or absence of pathogenic factors. True malaria involves pathogens, where the meeting of Wei Qi determines cessation and onset. Malaria-like conditions without pathogens involve the struggle between water and fire determining excess and deficiency. The former is located in the exterior, treated by expelling pathogens; the latter is located in the interior, treated by supporting healthy qi. One should not assume that similar mechanisms imply identical treatments. The subtle distinction between similarity and difference is critical to life and death; students must examine this carefully.)