ABSTRACT
This chapter introduces theories of the causes of smallpox which developed through several centuries in pre-modern China. It shows different concepts of a contagious disease in traditional Chinese medicine. In 610, when Chao Yuanfang complied a medical text, the Zhu bing yuan hou lun, which was concerned with the origins and symptoms of disorders, he classified smallpox under four of his various categories of disease, cold-damage disorders, seasonal vapour, hot disorders, and epidemic. From the Five Dynasties and the Song and Yuan period onwards, smallpox was gradually regarded as a paediatric disease. After the Five Dynasties and Song period, the prevalent theory concerning smallpox aetiology was based on the concept of "foetal toxin", heat toxin given to the infant by its mother, or father, or by both. The idea of essential external factors in a case of smallpox was widely accepted in pre-modern China. The concept of the foetal toxin was complex in pre-modern China.
