Introduction: Rheumatoid arthritis (RA) is a chronic and systemic inflammatory disorder affecting multiple joints. Although etiology of RA is not fully understood, TNF-alpha has been shown to play a central role in the pathogenesis of RA. TNF-alpha stimulates proliferation of synovial cells and the production of matrix metalloproteinases by chondrocytes and synovial cells, and induces the release of other pro- inflammatory cytokines, leading to joint destruction. Objectives: The aim of the present study was to investigate the therapeutic effects of sunlavin, an arthritis relief tea on antigen- induced arthritis in rabbits. Methods: Arthritis of the knee joints was induced by ovalbumin injection into the joint spaces of pre-immunised rabbits. For time course experiments sunlavin was administered to rabbits for 7, 20, 34, and 49 days. Histopathological analysis of the synovial tissue was performed. Level of tumor necrosis factor-alpha (TNF-alpha), erythrocyte sedimentation rate (ESR), C reactive protein (CRP) level, and white blood cells count (WBC) were measured. Results: Sunlavin reduced joint swelling of antigen-induced arthritis model of rabbits. Histological examination revealed that sunlavin reduced edematous changes and infiltration of inflammatory cells in the synovial tissues. Increases in ESR, CRP, and WBC were reduced up to 52% by sunlavin. Moreover, sunlavin decreased blood level of TNF-alpha (21%) in rabbit model of antigen-induced arthritis suggesting that sunlavin ameliorates inflammatory response in arthritic joints by inhibiting THF-alpha. Discussions and conclusions: We speculate that the effect of sunlavin might be affected by the tissue environment and the disease state, that is, the effect of sunlavin on inflammation may change during the inflammatory process. Sunlavin can be a potential anti-inflammatory agent for acute and chronic phase of inflammation.