Objectives . The types of Sasang constitutional medicine (SCM) have definite effect on response to herbal drugs. The majority of human P45O dependent xenobiotic metabolism is carried out by polymorphic enzymes which can cause abolished, altered or enhanced metabolism. Therefore, we evaluated the relation of major CYP2C19, 2D6 polymorphism with Sasang types. Methods : 214 healthy subjects were recruited with informed consent; 172 among them had Sasang diagnosis by QSCC2. CYP2D6, 2C19 polymorphism were determined by PCR-RFLP method. Results : None of the Sasang types showed significant difference in CYP2D6, 2C19 polymorphism. However, the Tae-um type showed relatively low frequency of CYP2D6 $^{*}$10/$^{*}$10 polymorphisms with low activity (p=0.110). In the So-yang type, specific $^{*}$3/$^{*}$3 genotype which is a poor metabolizer of CYP2C19$^{*}$3 was detected (p=0.078).Conclusion . These results suggest that the Tae-um type which is said to have high liver function in SCM has the tendency of high drug-metabolizing enzyme activity. With further study, the CYP polymorphism could serve as a scientific tool for SCM diagnosis.