Objectives The anti-inflammatory and anti-arthritic effects of Youngseonjeatonguem (靈仙除痛飮, YSJTU) was evaluated in a cellular model using RAW264.7 macrophages, which are involved in osteoarthritis (OA), and an animal model using Sprague-Dawley (SD) rats, and a possible mechanism of anti-arthritic actions of YSJTU was presented. Methods RAW264.7 macrophages were activated by lipopolysaccharide (LPS). The production of pro-inflammatory cytokines (tumor necrosis factor [TNF]-α, interleukin [IL]-1β, and IL-6) and inflammatory mediators (nitric oxide [NO] and prostaglandin E2 [PGE2]) was determined by ELISA and Griess assay, respectively. Western blot was performed to determine inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression. OA was induced by intra-articular injection of monosodium iodoacetate (MIA) into the right knee joint of SD rats. Results In RAW264.7 macrophages, YSJTU reduced LPS-induced production of TNF- α, IL-1β, and IL-6. In addition, YSJTU inhibited LPS-induced production of NO and PGE2 by suppressing iNOS and COX-2 expression. In SD rats, YSJTU improved MIA-induced OA by reducing swelling, skin heat, and cartilage degradation. In addition, YSJTU reduced serum levels of TNF-α, IL-1β, and IL-6, along with its significant decrease in serum levels of NO and PGE2. Conclusions These results suggest that YSJTU may exert anti-arthritic effect, at least in part, by inhibiting macrophage-mediated joint inflammation. (J Korean Med Rehabil 2023;33(4):1-14)