Abstract: OBJECTIVE To observe the effects of Aconitum soongaricum and its processed products on collagen-induced arthritis (CIA) rats. METHODS Rats were ramdomized into normal group, model group, positive group, Aconitum soogaricum group and its processed products groups of high-, middle- and low-dose group. CIA rat model was established by bovine collagen Ⅱ emulsion and Freund's complete Adjuvant(FCA). After inflammation, each group were given drug intragastrically for 6 weeks. Ankle swelling degree of CIA rats was observed. Content of IL-2, SA, TNF-α in serum of each group were determined by ELISA method. CIA rats knee synovial membrane was taken to observe its histopathology changes after pathological section and hematoxylin-eosin(HE) staining. RESULTS ① The swelling degree, the content of IL-2, SA, TNF-α in model group was higher (P<0.01) than normal group. The inflammatory lesion of knee synovial membrane in model group was obvious. ② Compared with model group, the swelling degree, the content of IL-2, SA, TNF-α in Aconitum soongaricum and all of its processed products groups were lower (P<0.01 or P<0.05). ③ Compared with model group, Aconitum soongaricum and all of its processed products groups could ameliorate inflammatory lesion of CIA rats' knee synovial membrane. CONCLUSION Aconitum soongaricum and all of its processed products groups are proved to be anti-inflammatory.