This paper presents an analysis of the relationship between venereal disease (VD), prostitution and the rise of modern medicine in China from the middle of the nineteenth century up to the communist victory in 1949. The first part shows that western and western-trained physicians were ill-equipped to deal with China's numerous diseases in the absence of a strong and modern state. The second part discusses the nature and relevance of the missionary medical sources on which this study is based. In spite of their lack of precision and coherence, such data can be used to highlight and document a little known aspect of China's social history. The third part aims at assessing the extent of venereal disease in China. It concludes that venereal diseases were a major public health problem before 1949 in the whole country. Tens of millions of Chinese were infected with syphilis without receiving adequate treatment. The last part examines the discourse generated by physicians on prostitution and VD. The debate originated from other sectors of society and the medical community did not take a leading role in this movement. The medical community was very narrow and never achieved the status and influence it had in Western countries. Chinese society remained oblivious to ‘syphilophobia’ as it ran counter to its sexual culture.