For many years hypercholesterolemia has been associated with the development of atherosclerosis in experimental animals and with an increased incidence of coronary thrombosis in man. The correlation between elevated serum cholesterol and atherosclerotic heart disease has led to the therapeutic use of cholesterol-reducing diets and medications in patients with this disorder. On the other hand, the correlation between cerebral thrombosis and hypercholesterolemia has been less well studied, and efforts to reduce serum cholesterol in this form of atherosclerosis have not been widely recommended. Patients with cerebral atherosclerosis might be expected to have an elevation of serum cholesterol comparable to that found in coronary vascular disease; however, differences in age, sex, and racial incidence of the 2 diseases could possibly produce differences in the level of this serum lipid. Coronary thrombosis, for example, occurs much more frequently in males,1 appears in lower age groups,2 and has a lower incidence