The purpose of this study was to investigate the anti-inflammatory effects of aqueous extract from Sophora Japonica (SJ) on the RAW 264.7 cells. To evaluate the anti-inflammatory effects of SJ, we examined the cytokine productions including nitric oxide (NO), interleukin (IL)-1b, IL-6 and tumor necrosis factor-a (TNF-a) in lipopolysaccharide (LPS)-induced RAW 264.7 cells and also inhibitory mechanisms such as mitogen-activated protein kinases (MAPKs) and nuclear factor kappa b (NF-kB) using Western blot. SJ inhibited LPS-induced production of NO, TNF-a but not of IL-1b and IL-6 in RAW 264.7 cells. SJ inhibited the activation of MAPKs such as extracelluar signal-regulated kinase (ERK 1/2), c-Jun NH2-terminal kinase (JNK) and p38 but not of NF-kB in the LPS-stimulated RAW 264.7 cells. In conclusion, SJ down-regulated LPS-induced NO and TNF-a productions via MAPKs, which could be a clinical basis for inflammatory diseases and autoimmune diseases.