To study the effects of Changyuning Granule (CYN) on ulcerative colitis induced by dinitrochlorobenzene/ethanoic acid in rats,and to explore its mechanism.Methods:Male SD rats were divided into 6 groups:the normal group,the model group,the low,medium and high dose group of CYN and the sulfonylamine group (SASP).The ulcerative colitis model was induced by dinitrochlorobenzene/ethanoic acid.Disease activity index (DAI),colonic mucosa damage index (CMDI) and pathological histology were assessed.Serum IL-β,TNF-α,and calcium protein (Calproteein,CP) were detected by ELISA.The expression of CP in colonic mucosa was detected by Western blot.Results:DAI results suggested that the model was successful.Compared with the normal group,IL-β,TNF-α,and CP in the serum of the model group were significantly increased,and the index of CMDI,colonic mucosa CP were significantly increased.The DAI,CMDI,and mucosal CP in the colon tissue of each group of Changyuning Granules were decreased,and the levels of IL-,TNF-,and CP in serum were also significantly decreased.Conclusion:CYN Granule can effectively relieve the ulcerative colitis induced by dinitrochlorobenzene/ethanoic acid in rats.The mechanism may be related to down-regulation of IL-β and TNF-α expression and reduction of CP level.