This paper examines the controversy surrounding the 1990 'Bristol Study' as an indicator of developments in health activism and medical research in the United Kingdom in the subsequent decade, and as a case study of the motivations prompting people to become activists. Researchers investigating complementary therapies at the Bristol Cancer Help Centre found the therapies were associated with poorer survival prospects. However, the study was later shown to be seriously flawed. Stung by researchers' insensitivity, participants formed the Bristol Study Support Group (BSSG) to lobby for new funding and journal review procedures, and for participants to be co-investigators. Their agenda was symptomatic of activists increasingly seeking to become integral to research processes. Groups like the BSSG were helped by the New Labour party's interest in increasing civic involvement. However, activist participation was limited to research planning and administration, not results interpretation, suggesting that, while activists could influence the politics of 1990s medical research, research practice was immune.