This chapter studies the complete socialisation and naturalisation of opium smoking in the late nineteenth and early twentieth centuries. What happened to the Ming–Qing socio-economic transformation when western capitalist actors appeared on the China stage is a subject that has been at the heart of academic debates. Albert Feuerwerker believes that feudal autocracy had ‘prevented the sprouts of capitalism in agriculture from developing into the dominant economic form’, and that imperialism had aborted ‘the promising capitalist sprouts in handicraft industry and commerce’. Others, however, have taken the view that foreign trade and investment contributed to China's modernisation. Hao Yen-p'ing stresses that ‘China's trade with the West during the nineteenth century gave impetus to a full-fledged mercantile capitalism that constituted a commercial revolution’, while Gregory Blue has stated that ‘the opium trade was instrumental in integrating China into the world market’. It is true that western capitalism destroyed or weakened some industry and commerce, but it also helped to create and strengthen others. What must be understood is the intimacy and the friction between the treaty ports and the old cash-cropping market town economic structure, because both contributed to the complete socialisation and naturalisation of opium smoking. The commerce and consumption of opium flourished under this dual system, as foreign opium satisfied the rich and the urbanites while Chinese opium met the demand of the entire nation.