['Asiasari sieboldii is widely used in Korean traditional medicine. In this study, we examined the anti-inflammatory effects of A. sieboldii ethanolic extract (ASEE) in a lipopolysaccharide (LPS)-induced murine macrophage RAW264.7 cell, and then sought to understand the mechanism(s) underlying the observed effects.', 'The production levels of nitrite oxide (NO), prostaglandin E₂ (PGE₂) and cytokines were measured using the Griess reagent and enzyme-linked immunosorbent assays (ELISA), while the cell protein expression levels were monitored by Western blot analysis.', 'Our results revealed that ASEE had prominent inhibitory effects on NO, PGE₂, interleukin (IL)-6 and tumor necrosis factor (TNF)-α production, as well as the expression of inducible nitrite oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), in LPS-induced RAW264.7 cells. Mechanistically, ASEE upregulated the expression of hemeoxygenase-1 (HO-1), and inhibited the nuclear translocation of nuclear factor (NF)-κB by preventing degradation of inhibitor κB-α (IκB-α).'] Does asiasari sieboldii suppress inflammatory mediators through the induction of hemeoxygenase-1 expression in RAW264.7 cells?