Objectives : The purpose of this study was to evaluate whether herbal medication may injure the liver function and kidney function. We clinically studied the changes of biochemistry and complete blood cell count in patients who were hospitalized in Korean hospital. Methods : The subjects were 160 patients admitted in Kangnam Korean hospital, Kyung Hee, whose mean duration of medication was 70 days(min 30, max 252). All patients had been checked biochemistry and complete blood cell count for 30 days since their hospitalization. Results : Aspartate aminotransferase(AST), alanine aminotransferase(ALT), alkaline phosphatase(ALP), blood urea nitrogen(BUN) and Creatinine(Cr) decreased significantly on discharge, compared with the values of admissoin(P<0.05). Total protein significantly elevated on dischrge compared with the values of admisson(P<0.05). Conclusions : This study suggests that even though there are few toxic herbal medicines, in general, herbal medications which are prescribed by oriental medicine doctors should be carefully administered not to hurt liver and kidney function.