A B S T R A C TObjective: To investigate the effect of different concentrations of lauric acid on Intercellular Adhesion Molecule-1 (ICAM-1) and Vascular Cell Adhesion Molecule-1 (VCAM-1) expression in IFN-g stimulated human monocytic THP-1 cell line. Methods: THP-1 cell were cultured using Roswell Park Memorial Institute medium supplemented with 10% fetal bovine serum. THP-1 monocytes were firstly differentiated into macrophages by using phorbol-12-myristate-13-acetate. IFN-g response test was performed and total cellular RNA was extracted using TRI Reagent ® LS before q-RT-PCR was carried out. Subsequently, IFN-g treated THP-1 macrophages were stimulated with increasing doses of lauric acid for another 24 h, before q-RT-PCR.Results: The mRNA expression levels of ICAM-1 and VCAM-1 were normalized to bactin and relatived to the untreated cells. The expressions of ICAM-1 and VCAM-1 were significantly induced in cells treated with 10 ng/mL of IFN-g. This showed that IFN-g could up-regulate inflammatory process and may cause atheroma formation. MTT assay was carried out to investigate the effect of lauric acid on undifferentiated and differentiated THP-1 cells. Although lauric acid did not have any significant impact on undifferentiated and differentiated THP-1 cell viability, the normalized fold expressions of ICAM-1 and VCAM-1 in IFN-g-treated THP-1 macrophages were decreased significantly in a dose dependent manner with the presence of increasing doses of lauric acid. Conclusions: This study successfully proved that lauric acid was able to antagonize the up-regulatory effect of IFN-g on ICAM-1 and VCAM-1 expressions in THP-1 macrophages. This indicates that lauric acid may be an anti-inflammatory therapeutic and prophylaxis agent for atherosclerosis.