To assess the relationship between the severity of stenosis in MCA territory and the differentiation of syndromes in oriental medical aspects, the general characteristics, the scores of stroke-pattern identification, and the findings of MRA were compared in 18 acute cerebral infarction patientshospitalized in Dept. of Internal Medicine, Pundang CHA Oriental Medicine Hospital from 1998 sep. 1 to 1999 sep. 31. We compared the scores of stroke-pattern identification with the severity of stenosis by Kruskall-Wallis test, and analyzed the relationship by Pearson correlation test. The P value under 0.05 was regarded as significant. The results are as follows: The incidence of stenosis(mild to complete occlusion) was 83.3%. There were significant difference of the mean scores according to the severity of stenosis in Yin deficiency pattern. We could also observe a strong relationship between the severity of stenosis and Yin deficiency pattern, whose Pearson correlation coefficient was 0.655 (P<0.05). These results showed that Yin deficiency pattern could be a major cause of cerebral infarction.