隋唐之間醫學典籍呈現豐富多元的小兒病因觀。根據醫學名家之見，小兒疾病的根源，多來自外在的人為因素，而除了外因、內因與不內外因三類型外，還包括小兒獨有的胎病、先天不足、將養不當、臟腑與血氣的病變、柔弱，以及成長發育的障礙等。在中古時期醫者的筆下，小兒的健康、壽夭、德行與社會成就，操之母親與乳養者之手，其病源甚至可溯及在胎期間，或懷孕前母親的生活起居、飲食、性情、健康與道德品質。據此，在既有的求子與生育任務上，醫學賦予女性更艱鉅的責任與壓力。當醫學將小兒疾病之過歸咎於母親與乳母的同時，對比出小兒的無辜。但即使可諉過他人，小兒本身臟腑與氣血的柔弱或不定，也常是病源。醫者從專業的立場強調小兒嫩弱，藉此建構小兒病因觀與身體理論，從而影響醫者的臨床診斷與治療，此一觀念與理論的開展與運用，是小兒醫學逐步專門化與獨立成專科的一大關鍵。在揭示小兒病因之際，男性醫者突破性別藩籬，巧妙地將醫療介入的層面，從診治疾病擴及養育小兒。至此，醫學文本化作對病家的規訓，樹立並擴大醫者的權威，宣示小兒醫學知識的專業化。女性與小兒更為弱勢化，女性須經醫者教導，始能正確照顧和養育小兒；原已氣勢微弱的小兒欲健康成長，更只能仰賴醫者、母親與乳母。

This paper aims to explore conceptions of childhood disease etiology during the Sui and Tang dynasties (581-907), and to examine important aspects of medical understanding regarding childhood diseases, children' bodies and their health.Medieval medical experts attributed pediatric disease not only to expected and unexpected climatic change, being frightened, as well as to accident, supernatural forces, worms, and diet, but also to factors such as a careless mothers during and after pregnancy, congenital factors, contagion, improper nursing and imbalanced body conditions. According to those experts, the diet, temper, health, behavior and moral character of the mother or wet nurse also influenced the child. Therefore, from the medical point of view, the mother was not only responsible for raising and caring for physically healthy offspring, but also for bearing and teaching good sons with high moral standards and social achievement.Pediatric experts put extra emphasis on the idea that many childhood diseases also resulted from their own frail and feeble bodies. They further used this idea to form basic conceptions of the child body, and applied it to diagnoses and treatments. These signified the professionalization and independence of pediatrics. At the time when male medical experts sought the origins of childhood diseases, they crossed the sex barrier to instruct females on the right ways of nursing children. In so doing, they extend the domain of pediatrics, empowered themselves with professional knowledge, and strengthened their authority over pediatrics and child caring. These are keys to the development of pediatrics in medieval China, and to the independence of pediatrics in the Northern Song dynasty.