CURRENT interest in the relationship between emotional stress and cardiovascular disease stems from several observations. First, traditional risk factors are absent in more than half of the newly encountered cases of coronary heart disease. This observation suggests that other as yet unrecognized risk factors contribute to the pathogenesis of coronary heart disease. Second, there is impressive evidence that psychosocial conflict, emotions, and patterns of behavior can and do play an important role in the pathogenesis of certain types of cardiovascular disease. For example, using animals, investigators have been able to induce and document a variety of disease entities, including sustained hypertension, renal failure, accelerated atherosclerosis, coronary insufficiency, myocardial infarction, cardiomyopathy, and sudden death. However, whereas animal studies are easily controlled, comparably objective and controlled studies in man remain uncommon. At the present time, conclusions drawn from clinical research are more often supported by guilt through association and inference.