Betulinic acid, a naturally occurring pentacyclic triterpenoid, is found in abundance in the outer bark of white birch (Betula alba). In this study, we investigated if betulinic acid affects cytokine expression from activated macrophage cells. ELISA result showed that stimulation of HL-60 cells with proinflammatory cytokine such as $TNF-{alpha}$ resulted in MCP-1 release into culture medium. In addition, transcriptional upregulation of MCP-1 in response to $TNF-{alpha}$ was observed by RT-PCR analysis. However, incubation of HL-60 cells with betulinic acid prior to $TNF-{alpha}$ treatment abrogated MCP-1 expression in transcription and translational level. Consistent with a number of studies which reported requirement of ERK activation for $TNF-{alpha}$ expression, Western blot analysis showed that $TNF-{alpha}-induced$ ERK activation was suppressed by pretreatment of HL-60 cells with betulinic acid. Taken together, our data indicate that betulinic acid exerts its anti-inflammatory effect through inhibition of $TNF-{alpha}-induced$ ERK activation which is required for the subsequent MCP-1 release.