Objective : The purpose of this study is to examine safety of herbal medicine on liver function and compare with western medicine. Method : 303 subjects of skin disease(vitiligo and psoriasis) were chosen at a local oriental medical clinic, and tested with a spot liver function test from Sept 1, 2006 to Dec 31, 2006. Subjects were grouped into untreated, herbal medicine, western medicine, and combination group by treatment record. Total bilirubin, AST, ALT and LDH was compared in each group, odds ratio and regression coefficient was calculated. Results : Subjects comprised of 116 individuals receiving western medication(38.28%), 54 receiving herbal medication(17.82%), 107 receiving combined forms of medication(35.31%), and 26 individuals without any types of medication(8.58%). With the mean age of 37.0 yr. 204 were male(67.3%), 99 were female(32.7%). Comparing variables of liver functions, there was no significant difference between the control and experiment groups. After adjusting potential confounders, monthly $eta$(SE) of multiple regression -0.009~0.000 for the herbal group, -0.005~0.000 for the western group, and -0.001~0.001 for the combination group. No significant difference between the groups. OR of T-bilirubin were 1.02, 1.05, and 1.04. AST were 0.92, 0.94, and 0.98. ALT were 0.85, 0.99, and 0.97. LDH were 0.96, 1.06, 1.00 for the herbal, western, and combination group, respectively. Conclusion : Comparing with western medication, herbal medication did not cause special ill-effect on the liver function based on liver function tests.