Aralia continentalis from Imsil (ICF-2), widely used in some countries of East Asia as an medicinal herb possesses diverse remedial values including anti-inflammatory, anti-febrile, analgesic and anti-spasmodic effects. The aim of this study was to investigate the anti-inflammatory and anti-arthritic effect of 50% ethanol extract of ICF-2 in the interleukin (IL)-1β-stimulated human chondrocyte, an in vitro model of osteoarthritis (OA). Human OA chondrocytes were treated with ICF-2 extracts of 50, 80 or 100 μg/ml, and subsequently with 10 ng/ml IL-1β, and further incubated for another 24 hrs. Ethanol extract of ICF-2 significantly inhibited IL-1β-induced expression of IL-6, IL-8, MMP-1, MMP-13 and COX-2, and PGE2 production, but not MMP-3 expression in the chondrocytes. ICF-2 extract also modulated the IL-1β-induced translocation of nuclear factor (NF)-κB (p65) into the nucleus and phosphorylation ERK, JNK and p38 of MAPK pathways. As an index chemical of ICF-2, continentalic acid exhibited a significant inhibitory activity on IL-1β-induced expression of IL-6, IL-8 and MMP-13, of which activity was compatible with that of ICF-2 extract including an equivalent amount of continentalic acid. Kaurenoic acid, another representative chemical component, also inhibited the expression of those proteins at the concentration of 20 times higher than continentalic acid. These results suggested that the 50% ethanol extract of ICF-2 and its diterpene component, continetalic acid have a significant anti-inflammatory effect in the IL-1β-stimulated human OA chondrocytes. Thus, the ICF-2 extract can be a potential candidate for developing new medicines or dietary supplements for the treatment of osteoarthritis and continentalic acid might be the active ingredient. (This research was supported by the Ministry of Agriculture, Food and Rural Affairs (MAFRA), through the 2015 Healthy Local Food Branding Project of the Rural Resources Complex Industrialization Support Program)