['Fuyuan Decoction (FYD) is an empirical formula of treating Bi Zheng in traditional Chinese medicine (TCM). Despite the fact that the efficiency of FYD on treating osteoarthritis has been verified in clinic, the underlying mechanisms are not totally understood. This study was to investigate the effects and mechanisms of FYD on nitric oxide (NO) production and nuclear factor (NF)-κB activation in interleukin (IL)-1β-stimulated chondrocytes.', 'SW1353 human chondrosarcoma cells were pretreated with various concentrations of FYD-containing serum (FYD-CS), and then were stimulated by IL-1β. Amounts of NO were determined by Griess reaction assay. Inducible NO synthase (iNOS) expression, inhibitor-κBα (IκBα) degradation and nuclear translocation of p65 protein were determined by Western blot assay. DNA binding activity of NF-κB was determined by ELISA assay using Trans AM(™) kit for p65.', '10% and 20% (v/v) FYD-CS significantly decreased NO production in a concentration-dependent manner (p<0.05 or p<0.01) as compared to control in IL-1β-induced SW1353 cells. Besides, 10% and 20% FYD-CS also significantly reduced iNOS protein expression by about 60% and 70% (both p<0.01), respectively. Furthermore, 10% and 20% FYD-CS markedly decreased IκBα degradation by about 45% and 26% (p<0.01 or p<0.05), lessened P65 content in the nucleus by about 28% and 60% (both p<0.01), and repressed DNA binding activity of P65 by about 30% and 45% (both p<0.01) in IL-1β-induced SW1353 cells.'] Does fuyuan Decoction inhibit nitric oxide production via inactivation of nuclear factor-κB in SW1353 chondrosarcoma cells?