Objectives: Liver function tests are used as screening tests for liver injuries, but their inaccuracy on positive predictive values can result in numerous false positive results. We investigated the incidence of liver function test abnormalities of patients who came to an oriental medicine hospital, in order to present a practical way to rule out false positive results for other studies designed to investigate the safety of Korean herb medicine. Methods: We analyzed the medical records and liver function test results proceeded at admission of all in-patients admitted to Jaseng Oriental Medicine Hospital, from July 2008 to June 2009. Results: Among 1,117 inpatients, 941 executed liver function tests on admission, and 40 were excluded due to their diagnosed liver disease. 747 (82.9%) of 901 enrolled patients were within the normal range of all liver function tests, and 140 (15.5%) and 14 (1.6%) were classified as "abnormalities of liver tests" and "liver injury" respectively, according to the CIOMS (Council for International Organizations of Medical Sciences) criteria. Conclusions: According to the results, among the outcomes of liver function tests proceeded among the patients admitted to the oriental medicine hospital, excluding who were diagnosed with liver disease, 17.1% showed abnormality. This means simple liver function test results are not sufficient in determining liver toxicity of Korean herb medicine (KHM).