摘要隋以前天花已经传入中国，隋唐时期对天花已经有了较为准确的描述，已经意识到其为烈性传染病，能够通过症状和天花的外观初判预后，认为天花是热毒所致，是伤寒的一种。北宋早期认为痘疮是由于脏腑积热，后期提出了天花是胎儿吸食了母体的秽液导致，为胎毒说之雏形；已经能够辨别水痘、麻疹及天花的不同。明清时期，“胎毒”外感说已成为主流；观察到感染一次天花以后不会再感染这一免疫现象；对天花的症状有了细致描述，能准确预后。可以看出古代医家们对于天花的认识是随着时间的进展不断深入的，这些认识为人痘接种术的发明奠定了基础。

abstractsSmallpox was believed afferent before the Sui Dynasty. Some relatively accurate descriptions about smallpox were found in the Sui and Tang Dynasties. Smallpox was recognized as a severe infectious disease caused by pathogenic heat by the observation of its symptoms and appearance. It was believed that smallpox was caused by the heat accumulation in the Zang-Fu organs in the early period of the North Song Dynasty. After that, it was believed caused by the fetus ingesting the filthy liquid from the mother as the prototype of the fetal poison theory. This means that ancient Chinese physicians were able to distinguish the differences among chickenpox, measles and smallpox at that time. The exogenous theory of fetal poison became the mainstream in the Ming and Qing dynasties. Smallpox, therefore, was confirmed not to be re-infected after once infection, and was specifically described with the symptoms and the precise prognosis. It can be seen that the understanding of smallpox by ancient Chinese physicians developed with time, and these understandings opened a way for the invention of the human pox vaccination.