Ruxiang (Gummi olibanum), the dried gum resin of Boswellia carterii (BC), has been used in traditional Chinese medicine to alleviate pain and inflammation for thousands of years. In this random, blinded study, the anti-arthritic effects of a BC extract were observed and compared to vehicle control in a Lewis rat adjuvant arthritis model (n=8/group). Arthritis was induced by injecting CFA subcutaneously into the base of the tail, and the extract was administered orally (i.g.) for 10 consecutive days beginning on day 16 after the injection. Arthritic scores, paw edema, and the local tissue pro-inflammatory cytokines tumor necrosis factor alpha (TNF-alpha) and interleukin-1 beta (IL-1beta) were assessed. Toxicity and adverse effects of the extract were evaluated. At 0.90 g/kg per day, BC significantly decreased arthritic scores between days 20 and 25 (p<0.05) and reduced paw edema on days 18, 20 and 22 compared to control (p<0.05). It also significantly suppressed local tissue TNF-alpha and IL-1beta (p<0.05). No major adverse effects were observed in animals during the repeated-dose treatment profile although mild fur discoloration was noted. The data show that BC extract has significant anti-arthritic and anti-inflammation effects and suggest that these effects may be mediated via the suppression of pro-inflammatory cytokines.