Objective: To study the effects of dexamethasone (DEX) on the proliferation and expression of the intercellular adhesion molecule-1 (ICAM-1) in human oral fibroblasts (FB), and to investigate the mechanism behind the beneficial effect of DEX in oral submucous fibrosis (OSF). Material and Methods: Fibroblasts were obtained from normal buccal mucosa (NM-FB) and OSF buccal mucosa (OSF-FB) and cultured in vitro. Then the cell proliferation of fibroblasts was incubated with and without DEX in 10% fetal calf serum for 48 hours at 37œC in 5% CO₂. The air was monitored by thiazolyl blue (MTT) assay and ICAM-1 expression in the fibroblasts was measured using enzyme-linked immunosorbent assay (ELISA). Results: OSF-FB exhibits specific growth characteristics and increased ICAM-1 expression may be a causative factor of OSF. DEX can directly inhibit human oral fibroblast proliferation and down-regulate ICAM-1 expression in oral mucosal FB, which may have implications for the judicious topical usage of DEX in the therapy of OSF.