Abstract
This paper reconstructs and analyzes the content and context of the debate over the efficacy of vitamin C in the treatment of cancer, and compares it with medical responses to, and evaluations of, two other cancer drugs—the cytotoxic drug 5-FU (conventionally used in the treatment of gastrointestinal cancers) and the ‘naturally-occurring’ (but recombinant DNA-produced) drug interferon. This comparative approach is designed to facilitate the integration of microsociological and structural levels of analysis of the processes by which knowledge claims about therapeutic efficacy are evaluated by the powerful adjudicating medical community. It is argued that the assessment of medical therapies is inherently a social and political process; that the idea of neutral appraisal is a myth; that clinical trials, no matter how rigorous their methodology, inevitably embody the professional values or commitments of the assessors; and that judgements about experimental findings may be structured by wider social interests, such as consumer choice or market forces. It is concluded that the necessarily social character of medical knowledge cannot be eliminated by methodological reform, and that this has important implications for the social implementation of medical therapies and techniques.