Multicentre randomized clinical trials in Europe over the past decade have made a major contribution to the practice of cardiology and will increasingly do so when the Single Europe Act becomes a fact of life in 1992. The arguments for independent scientifically based research organizations and their role in the area of coronary artery disease are outlined. These include cost-benefit considerations, the science of clinical trials, data acquisition techniques and data management requirements. The role of the pharmaceutical industry in relation to the investigator-trialist is discussed. A critique of the current fashion 'Big is beautiful', with arguments against 'simplicity' and 'large size' and the need for 'credibility' is provided. Applicability of data from trials and their economic usefulness and validity in terms of sound pathophysiological hypotheses are also discussed and illustrated by using the CABRI trial as an example.