TMS is an evaluation of the common belief that emotional factors and physical effort may be responsible for acute coronary thrombosis. The critique distinguished acute myocardial infarction, which is the result of acute coronary thrombosis, from acute myocardial necrosis, which occurs independent of acute coronary thrombosis, and from angina pectoris, which it is recognized may be precipitated directly by emotional factors or physical effort. Workmen''s Compensation decisions relating coronary thrombosis to emotion and physical effort are based on time relationship and not on any controlled studies. Coronary thrombosis generally occurs without a preceding severe or unusual effort or an unusual emotional stress. The studies relating emotions to changes in serum lipids may apply to coronary atherosclerosis but not to coronary thrombosis. Behavior patterns described as characteristic of coronary-prone patients are nonspecific and many patients who suffer from coronary thrombosis do not have the characteristic behavior pattern. The increased incidence of coronary thrombosis attributed to the stress of modern competitive society may be attributed to many other factors. Deficient knowledge of the process of thrombosis hampers studies which attempt to relate physical exertion and emotion to coronary thrombosis.