小儿气禀纯阳，脏腑易得生热，阴阳气迁，熏蒸于外，致令身热也。肝热则两眼赤肿，
流泪羞明，或生翳瘴。心热则口内生疮，小便赤，淋沥不通。肺热则鼻衄不止，大便秘结。
脾热则生重舌木舌，流涎流沫。胃热则口作臭。肾热则耳聋，或出脓血。至于五脏蕴蓄风热毒风，
令儿面赤如绯，五心烦热，四肢温壮，痰涎壅盛，目涩多渴，上冲咽喉，则与气血相搏，结
聚壅盛而成喉闭也。大抵小儿多因热生风，风生惊。欲儿无病，先清其热，此所谓拔本塞源
者也。
杨氏曰∶小儿病，惟热居多。夫热有潮热、惊热、夜热、余热、实热、虚热、表热、里热、
食热、疳热、壮热、烦热、气热、血热、积热、郁热、风热、客热、癖热、疮疹热，诸热大
同而小异。热之始发，必有所因也。潮热者，发歇有时。惊热者，颠叫恍惚。夜热者，夕发旦止。
余热者，寒邪未尽。实热者，壮盛壅滞。虚热者，气血俱虚，脾胃虚热。表热者，轻手按
之便觉，或因腠理感伤。里热者，大便秘结，小便赤黄。食热者，浓味之变，乳母所遗。
疳热者，腹大面黄，身热形瘦。壮热者，一向不止。烦热者，心燥不安。积热者，颊赤口疮。
风热者，汗出风热。客热者，去来不定。癖热者，腹中有块。郁热者，怫热闷乱。痰热者，
涎嗽引饮。疮疹热者，耳、鼻尖冷。诸证得之，各有所归，其间或有三两证交互者，宜随其
轻重而处治之。
小儿先天禀受的气血属于纯阳之体，脏腑容易滋生内热。随着阴阳之气的变动，热气熏蒸于体表，从而导致身体发热。肝有热邪，则双眼红肿，流泪且畏光，或者生成翳障。心有热邪，则口腔内生疮疡，小便颜色深红，排尿淋漓不畅。肺有热邪，则鼻出血不止，大便秘结不通。脾有热邪，则生重舌、木舌，流口水或口角溢沫。胃有热邪，则口中发出臭味。肾有热邪，则耳聋，或者流出脓血。至于五脏蕴蓄风热、毒风，导致患儿面色红如绯色，五心烦热，四肢温热壮盛，痰涎壅盛，眼睛干涩且口渴严重，热气上冲咽喉，与气血相互搏结，凝聚壅滞而成为喉闭证。大体而言，小儿多因热而生风，因风而生惊厥。想要孩子不生病，首先要清除其体内的热邪，这就是所谓的“拔本塞源”（从根本上解决问题）。
杨氏说：小儿的疾病中，热证占大多数。热证分为潮热、惊热、夜热、余热、实热、虚热、表热、里热、食热、疳热、壮热、烦热、气热、血热、积热、郁热、风热、客热、癖热、疮疹热等，这些热证大同小异。热证的初发，必定有其起因。潮热，是指发热有定时发作和停止的特点。惊热，是指患儿尖叫、神情恍惚。夜热，是指傍晚发作，清晨消退。余热，是指寒邪尚未完全清除。实热，是指正气强盛但邪气壅滞。虚热，是指气血俱虚，脾胃虚弱产生的虚热。表热，是指轻按皮肤即能感觉到热度，或因腠理感受外邪所致。里热，是指大便秘结，小便赤黄。食热，是由于食用浓味食物变化而来，或由乳母饮食不当遗留给婴儿的。疳热，是指腹部胀大、面色萎黄、身体发热且形体消瘦。壮热，是指持续高热不退。烦热，是指心中烦躁不安。积热，是指两颊发红、口腔生疮。风热，是指出汗后感受风热。客热，是指发热来去不定。癖热，是指腹中有肿块。郁热，是指体内郁结发热、闷乱不适。痰热，是指痰涎咳嗽、引水自救。疮疹热，是指耳朵和鼻尖发冷。以上各种证候，各有其归属，其间或有二三个证候交互出现的情况，应当根据病情的轻重来进行治疗。
Children are constitutionally endowed with "pure Yang" (Chunyang, a state of vigorous growth and metabolic activity), making their Zang-Fu organs prone to generating internal heat. As Yin and Qi undergo changes, the steaming effect of heat manifests externally, resulting in fever. Liver Heat (Gan Re) causes redness and swelling of both eyes, tearing, photophobia, or the formation of corneal opacities (Yi Zhang). Heart Heat (Xin Re) leads to oral ulcers, dark urine, and dysuria with dribbling. Lung Heat (Fei Re) results in persistent epistaxis and constipation. Spleen Heat (Pi Re) causes double tongue (Zhong She), wooden tongue (Mu She), drooling, or foaming at the mouth. Stomach Heat (Wei Re) causes halitosis. Kidney Heat (Shen Re) leads to deafness or the discharge of pus and blood from the ears. Furthermore, if Wind-Heat (Feng Re), Toxic-Wind (Du Feng), etc., accumulate within the five Zang organs, it may cause the child's face to turn crimson, accompanied by vexation and heat in the five centers (Wu Xin Fan Re - palms, soles, and chest), warmth and fullness in the four limbs, copious phlegm and saliva, dry eyes, excessive thirst, and upward rushing of heat to the throat. This heat clashes with Qi and Blood, condensing and obstructing to form Throat Closure (Hou Bi - acute obstruction of the airway due to swelling). Generally speaking, children often develop Wind (Feng) due to Heat, and Convulsions (Jing) due to Wind. To prevent illness in children, one must first clear their internal Heat; this is referred to as "pulling up the root and blocking the source" (Ba Ben Sai Yuan - addressing the fundamental cause).
Yang Shi stated: Among pediatric diseases, Heat syndromes are predominant. Heat syndromes include Tidal Fever (Chao Re), Fright Heat (Jing Re), Night Fever (Ye Re), Lingering Heat (Yu Re), Excess Heat (Shi Re), Deficiency Heat (Xu Re), Exterior Heat (Biao Re), Interior Heat (Li Re), Food Heat (Shi Re), Malnutrition Heat (Gan Re), High Fever (Zhuang Re), Vexatious Heat (Fan Re), Qi Heat (Qi Re), Blood Heat (Xue Re), Accumulation Heat (Ji Re), Stagnant Heat (Yu Re), Wind-Heat (Feng Re), Guest Heat (Ke Re), Mass Heat (Pi Re), and Rash Heat (Chu Zhen Re). These various heats share commonalities but have minor differences. The onset of any heat syndrome must have a specific cause. Tidal Fever occurs at regular intervals. Fright Heat is characterized by screaming and trance-like states. Night Fever starts in the evening and resolves by morning. Lingering Heat indicates that Cold pathogens have not been fully expelled. Excess Heat involves robust vitality but pathogenic stagnation. Deficiency Heat arises from dual deficiency of Qi and Blood, specifically Spleen-Stomach deficiency heat. Exterior Heat is felt upon light palpation of the skin, often due to invasion of the Cou Li (interstitial spaces) by external pathogens. Interior Heat presents with constipation and dark yellow urine. Food Heat results from the transformation of rich flavors or transmission from the nursing mother's diet. Malnutrition Heat is characterized by abdominal distension, sallow complexion, fever, and emaciation. High Fever refers to continuous, unremitting fever. Vexatious Heat involves mental restlessness and anxiety. Accumulation Heat manifests as flushed cheeks and oral ulcers. Wind-Heat occurs after sweating when exposed to wind. Guest Heat comes and goes unpredictably. Mass Heat involves abdominal masses. Stagnant Heat presents with internal oppression, heat, and confusion. Phlegm-Heat is marked by salivation, cough, and a desire to drink. Rash Heat is characterized by coldness in the ears and nose tip. Each of these syndromes has its specific attribution. Occasionally, two or three syndromes may interact; treatment should be administered according to the severity of the condition.