Objectives : The aim of this study was to evaluate effects of herbal medicine and other associated factors for abnormal liver function tests(especially total bilirubin, AST, ALT, and ${gamma}GT$) levels in outpatients at an oriental medical clinic. Methods : A cross-sectional study based on clinical records was conducted on 1,871 patients at one Oriental medical clinic in Seoul, Korea. 504 patients received a liver function tests for screening and 497 patients ranging from the age of 4 to 74 were chosen for the study. Patients with basal liver disease or DM were excluded during the screening process. Patients were classified into case(abnormal) and control(normal) groups by normal liver function test references. Results and Conclusions : In this study, 33.0% of the patients were females, and 67.0% were males. The mean age was $34.7{pm}11.9$ years old. The mean total protein value was $6.78{pm}0.66g/dL$(male $6.79{pm}0.61$, female $6.76{pm}0.76$), albumin $3.89{pm}0.50g/dL$(male $3.94{pm}0.47$, female $3.81{pm}0.54$), total bilirubin $0.51{pm}0.35mg/dL$(male $0.54{pm}0.39$, female $0.45{pm}0.23$), AST $23.31{pm}18.22U/L$(male $26.37{pm}20.73$, female $17.09{pm}8.72$), ALT $33.49{pm}36.36U/L$(male $40.56{pm}41.77$, female $19.13{pm}12.64$), LDH $258.07{pm}74.84mg/dL$(male $263.68{pm}73.77$, female $246.70{pm}75.92$), and ${gamma}GT$ $39.64{pm}59.16U/L$(male $50.15{pm}69.43$, female $17.83{pm}8.36$). The percentage of abnormal total bilirubin levels(>1.0) in these patients was 2.6%, abnormal AST levels(>39m, >29f) 8.5%, ALT levels(>47m, >32f) 18.8%, and ${gamma}GT$ (>50m, >40f) 19.9%.