This chapter focuses on the history of Wilson’s disease, a rare disease of copper metabolism, in the second half of the twentieth century. It analyses medical practice through a comparison of the development of two specific drugs, penicillamine in the United Kingdom in the 1950s, on the one hand, and zinc in the USA in the 1970s, on the other hand. It evidences changes in the field of ethics, regarding economic dimensions and regarding the division of labour, but no major change regarding the criteria of scientific objectivity. Thus, it concludes that the emergence of the interrelated categories of rare diseases and of orphan drugs resulted from changes in the regulatory framework for drug development in the United States in the 1960s, but not from changes in medical practice itself.