Objective To investigate whether ginsenoside Rg1 (Rg1) inhibits the expression of potentially pro-inflammatory cytokines by cultured murine microglial BV-2 cells stimulated with lipopolysaccharide (LPS). Methods An inflammatory cell model was structured by LPS-stimulated microglial BV-2 cells. The inflammatory cells were treated with Rg1 (10,20 and 40μmol/L) prior to LPS exposure. The effects on the mRNA and protein levels of pro-inflammatory enzymes, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), pro-inflammatory cytokines, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and inflammatory signaling proteins nuclear factor-κB (NF-κB) were analysed by reverse transcription -polymerase chain reaction (RT-PCR) and immunofluorescence staining assay. The effects of Rg1 on viability of BV-2 cells were measured by MTT assay. Results The results indicated that LPS-induced iNOS and COX-2 protein and mRNA expression levels decreased significantly by Rg1 in a concentration-dependent manner. Rg1 also had an effect on the expression of TNF-α, IL-1β and NF-κB through transcriptional and translational inhibition. In addition, Rg1 dose-dependently decreased the increasing expression