text: OBJECTIVE: To study the antiinflammatory effects of naphtha from different chemotypes of Cinnamomum camphora and natural borneol on the rat arthritis model induced by Freund's adjuvant. METHOD: The arthritis model was induced by injecting Freund's adjuvant in rat voix pedis dermis and the rats were randomly divided into seven groups: normal control group, model control group, triptergium wilfordii control group, borneol chemotype naphtha group, camphor chemotype naphtha group, isocamphane chemotype naphtha group and natural borneol group. Rats of the triptergium wilfordii control group were given orally 8.1 mg x kg(-1) triptergium wilfordii for 35 days, rats of the normal control group and model control group were given same volume water, and rats of other groups were given 80 mg x kg(-1) corresponding drug. We observed the rat common condition, weighed the rat body weight weekly, measured the degree of swelling of voix pedis every 4 days, weighed the thymus and spleen on the end of life, and measured the contents of cell factor TNF-alpha, IL-2, and IL-6 in rat blood serum. RESULT: As far as the arthrosis degree of swelling and the contents of cell factor TNF-alpha, IL-2, IL-6 were concerned, rats of model control group were higher than normal control group, and rats of other drug groups were lower than the model control group. The order of inhibition ratios of the arthrosis degree of swelling from high to low principle was isocamphane chemotype naphtha group, camphor chemotype naphtha group, borneol chemotype naphtha group and natural borneol group. All medication administration teams evidently reduced the contents of the IL-2 and IL-6, and the inhibition ratios were higher than 38%. In the case of the contents of TNF-alpha and IL-2, all groups were not evidently different. In the case of inhibition of IL-6, camphor chemotype naphtha group was better than borneol chemotype naphtha group and natural borneol group, the latter was better than isocamphane chemotype naphtha group. As far as the weight, thymus index and spleen index were concerned, all medication administration groups were not different. CONCLUSION: The different chemotypes of C. camphora have anti-inflammatory effect on the rat arthritis model induced by Freund's adjuvant, but pharmacological activity and mechanism of action are different. The study points out the clinical curative effects of the chemotypes of the kindred medicinal plant are different, and please consider the difference of chemotype in clinical application.