A new lignan, named acanthosessilin A ( 1), as well as eight known lignan and lignan glycosides 2− 9 were isolated from an ethanolic extract of Acanthopanax sessiliflorus fruits. The chemical structures were determined by spectroscopic methods, including HR-EIMS, 1D NMR ( 1H, 13C, DEPT), 2D NMR (gCOSY, gHSQC, gHMBC, NOESY), and IR spectroscopy. All isolated compounds were tested for the ability to inhibit LPS-induced nitric oxide production in RAW264.7 macrophages.