Sasang constitutional medicine is a major branch of Korean traditional oriental medicine. Constitutions of Sasang medicine refer to Taeyangin, Taeumin, Soyangin, and Soumin. The differences of disease severity to be shown in the constitution may be due to genetic factors. Therefore, we examined interrelationship among cerebral infarction, CI, angiotensin converting enzyme (ACE) gene polymorphism, and Sasang constitutional classification. We investigated the association between ACE genotype and CI by case-control study in a Korean population. We also classified CI patients and control group into groups according to Sasang constitutional medicine. 208 CI patients and 643 controls without CI were examined. ACE genotype was determined by 7.5 % polyacrylamide gel separation after DNA amplification. The ACE/DD genotype was not associated with CI. The frequency of Taeumin of Sasang constitutional medicine in patients with CI was significantly higher than that in controls (chi2=41.202, p<0.001). However, the Taeumin constitution did not enhance the relative risk for CI in the subjects with ACE/DD genotype. Although we did not find any association between ACE gene polymorphism and CI in Koreans, there were significant differences in allele frequencies between Koreans and Europeans, but not Japanese and Chinese populations. Furthermore, we first attempted to evaluate the efficacy of Sasang constitutional medicine, and to find an association with CI.