雷少逸曰∶《金鉴》云∶经曰∶冬伤于寒，春必病温，至夏为热病。热病者，乃冬伤正令之微寒，未即病也。倪氏
谓∶交立夏以来，久伏之气，随时令之热而触发，故初病即发热汗出，口渴心烦，不恶寒，而反恶热，脉来脉大之象，
是为热病也。《医通》曰∶邪非外来，故但热而不恶寒；热自内发，故口燥渴而多引饮。其邪既郁为热，不得复言为寒。
合而观之，热病因伏气者了然。然较晚发更发于晚，比诸温更伏于深。初起之时，宜用清凉透邪法。热势不衰，继用清
凉荡热法。倘有恶寒相兼，脉象举取浮紧，是有夏时暴寒所加，寒在外而热在里，先用辛温解表法，以透其外；外邪得
透，再用清凉之剂，以荡其里热也。设无浮紧之脉，又无恶寒之证，误用辛温之方，耗伤津液者，宜用清热保津法，加
西洋参、石膏治之。倘或兼之恶风，微微汗出，脉象举取浮缓，此表有风邪所加，风在外而热在里，当用辛凉解表法，
先解其外也。至于舌苔化燥，谵语昏狂，急用清凉荡热法，加紫雪丹治之。发斑者，加黄连、栀子；发疹者，加荷叶、
牛蒡。须知热病最易伤阴，当刻刻保阴为要，辛温劫液之剂，勿浪用也。
杨如侯曰∶夏至以后，炎暑司令，相火用事，人有发热身疼不恶寒，但大热而大渴者，为热病。《内经·热论》曰∶
凡伤寒而成温者，先夏至为病温，后夏至为病暑。暑病即热病也。夏至以前，气候不热，为春之暖，故病发犹名曰温。
温者，热之渐也。及夏至以后，气候渐热，为夏之暑，故病发则名曰热。《伤寒序例》云∶暑病者，热极重于温。是暑
病实热病也。伏气郁久而后发，发即大热大渴，仲景立白虎汤，实治热病之主方也。热病由下发上，由内发外，必经阳
明，故无论三阳，总以石膏之辛凉，乘势升散，知母之苦寒，靖少阴伏邪之源，甘草、粳米，维持中气。为一了百当。
杨上善曰∶冬伤于寒，轻者，夏至以前，发为温病；重者，夏至以后，发为暑病。
沈宗淦曰∶此言其常也。然春时亦有热病，夏日亦有温病。温，热之轻者也；热，温之重者也。故古人往往互称。
雷少逸说：《医宗金鉴》记载：经典中说，冬天感受寒邪，春天必定发生温病，到了夏天则称为热病。所谓热病，是因为冬天感受了正常气候中轻微的寒气，当时没有立即发病。倪氏认为：进入立夏之后，潜伏已久的邪气，随着时令的炎热而被触发，所以刚发病就出现发热、出汗、口渴、心烦的症状，不恶寒反而怕热，脉象洪大，这就是热病。《医宗必读》说：邪气不是从外直接侵入，所以只有发热而没有恶寒；热气从体内发出，所以口燥渴且大量饮水。既然邪气已经郁结化为热，就不能再说是寒邪。综合来看，因伏气（潜伏之邪）导致的热病原因就很清楚了。然而，它比“晚发”（冬季感寒春季发病）更晚发作，比一般的温病潜伏得更深。在初起阶段，适宜使用清凉透邪法。如果热势不退，接着使用清凉荡热法。如果有恶寒伴随，脉象轻取浮紧，这是夏季突发的寒邪侵袭，寒邪在体表而热邪在体内，先用辛温解表法，以发散体表的寒邪；待表邪发散后，再用清凉的药物，以清除体内的热邪。如果没有浮紧的脉象，也没有恶寒的症状，误用辛温的方剂，耗伤了津液，应该使用清热保津法，加入西洋参、石膏来治疗。如果兼有恶风，微微出汗，脉象轻取浮缓，这是体表受到风邪侵袭，风邪在表而热邪在里，应当使用辛凉解表法，先解除体表的邪气。至于舌苔变得干燥，出现胡言乱语、神志昏狂，紧急使用清凉荡热法，加入紫雪丹治疗。出现斑疹的，加入黄连、栀子；出现疹子的，加入荷叶、牛蒡。必须知道热病最容易损伤阴液，应当时刻以保护阴液为关键，不要滥用辛温劫夺津液的药剂。
杨如侯说：夏至以后，炎暑当令，相火（人体内的火热之气）主事，人如果出现发热、身体疼痛、不恶寒，只是大热和大渴的症状，这叫做热病。《黄帝内经·热论》说：凡是伤寒转化为温病的，在夏至之前发病的叫温病，在夏至之后发病的叫暑病。暑病就是热病。夏至以前，气候还不热，属于春天的温暖，所以发病仍然称为温。温，是热的渐进过程。等到夏至以后，气候逐渐变热，属于夏天的暑气，所以发病就称为热。《伤寒论序例》说：暑病的热势比温病更重。因此暑病实际上就是热病。伏气郁积很久后才发作，一发作就是大热大渴，张仲景创立了白虎汤（Gypsum and Atractylodes Macrocephala Decoction），这实际上是治疗热病的主要方剂。热病由下向上发展，由内向外发散，必经阳明经（Yangming Channel），所以无论涉及哪一经阳经，总要用石膏的辛凉性质，顺势升散邪气，用知母的苦寒性质，平息少阴经潜伏邪气的根源，用甘草、粳米，维持中焦脾胃之气。这是一举两得、周全妥当的方法。
Lei Shaoyi stated: The *Yizong Jinjian* (Golden Mirror of Medical Practice) records: The classics state, "If one is injured by cold in winter, one will inevitably suffer from warm disease in spring; by summer, it becomes heat disease." Heat disease refers to the slight coldness within the normal seasonal climate of winter, which does not cause immediate illness. Ni Shi believed that after the beginning of Summer (Lixia), the long-pent-up pathogenic qi is triggered by the heat of the season. Therefore, upon initial onset, there is fever, sweating, thirst, and irritability, without aversion to cold but rather aversion to heat, accompanied by a large pulse. This constitutes heat disease. The *Yitong* states: Since the pathogen is not directly external, there is only heat without aversion to cold; since the heat originates internally, there is dry mouth, thirst, and excessive drinking. Once the pathogen has stagnated and transformed into heat, it can no longer be described as cold. Synthesizing these views, the etiology of heat disease caused by latent qi (pent-up pathogenic factors) becomes clear. However, compared to "late-onset" diseases (winter cold manifesting in spring), it manifests even later; compared to general warm diseases, it lies deeper in latency. At the initial stage, the method of clearing heat and venting pathogens should be used. If the heat intensity does not subside, the method of clearing heat and purging fire should follow. If aversion to cold coexists with a superficially floating and tight pulse, this indicates sudden cold attack in summer, where cold is on the exterior and heat is on the interior. One should first use acrid-warm exterior-releasing methods to vent the exterior; once the exterior pathogen is resolved, cool agents should be used to purge the interior heat. If there is no floating-tight pulse or aversion to cold, and acrid-warm formulas are mistakenly used, depleting body fluids, the method of clearing heat and preserving fluids should be employed, adding American Ginseng (*Panax quinquefolius*) and Gypsum (*Shigao*). If accompanied by aversion to wind and slight sweating, with a superficially floating and slow pulse, this indicates wind pathogen on the exterior with heat on the interior; acrid-cool exterior-releasing methods should be used to resolve the exterior first. Regarding dry tongue coating, delirium, and manic stupor, urgently apply the method of clearing heat and purging fire, adding Zixue Dan (Purple Snow Pill). For macules, add Coptis Rhizome (*Huanglian*) and Gardenia Fruit (*Zhizi*); for papules/rash, add Lotus Leaf (*Heye*) and Arctium Fruit (*Niubang*). It must be understood that heat disease easily damages Yin; thus, preserving Yin at all times is paramount. Acrid-warm agents that consume fluids should not be used recklessly.
Yang Ruhou stated: After the Summer Solstice, intense heat commands the season, and Minister Fire (*Xianghuo*) is active. If a person presents with fever, body pain, no aversion to cold, but severe heat and severe thirst, this is called heat disease. The *Neijing·Re Lun* states: "All cases where Shanghan transforms into warm disease manifest as warm disease before the Summer Solstice and as summerheat disease after the Summer Solstice." Summerheat disease is heat disease. Before the Summer Solstice, when the climate is not yet hot, it is the warmth of spring, so the disease is still named warm disease. Warmth is the gradual progression toward heat. After the Summer Solstice, as the climate gradually heats up, becoming the summerheat of summer, the disease is named heat. The *Shanghan Xuli* states: "Summerheat disease involves heat more severe than warm disease." Thus, summerheat disease is essentially heat disease. Latent qi stagnates for a long time before manifesting; upon manifestation, there is severe heat and thirst. Zhang Zhongjing established Baihu Tang (White Tiger Decoction), which is actually the principal formula for treating heat disease. Heat disease develops from below upward and from inside outward, necessarily passing through the Yangming channel. Therefore, regardless of which Yang channel is involved, Gypsum (*Shigao*) with its acrid-cool nature is used to ascend and disperse the pathogen along with the trend; Anemarrhena Rhizome (*Zhimu*) with its bitter-cold nature calms the source of latent pathogens in the Shaoyin channel; Licorice Root (*Gancao*) and Rice (*Jingmi*) maintain the Qi of the Middle Jiao. This is a comprehensive and effective approach.
Yang Shangshan stated: Winter injury by cold, if mild, manifests as warm disease before the Summer Solstice; if severe, it manifests as summerheat disease after the Summer Solstice.
Shen Zonggan stated: This describes the general rule. However, there are also heat diseases in spring and warm diseases in summer. Warmth is lighter heat; heat is heavier warmth. Therefore, ancients often used the terms interchangeably.