ABSTRACT Purpose: To explore effect and mechanism of olsalazine of Chinese generic drugs on ulcerative colitis induced by dextran sulfate sodium salt (DSS) in BALB/c mice. Methods: The mouse model of ulcerative colitis was induced by free drinking of 3% (w/v) DSS aqueous solution for seven days. The mice were treated with olsalazine (0.6 g·kg-1) of Chinese generic drugs. The therapeutic effect of olsalazine on ulcerative colitis mice was evaluated by measuring disease activity index (DAI), colonic mucosal injury index (CMDI), histopathological score (HS), and detected the expression levels of interleukin (IL)-2, IL-10, tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), IL-1β in serum and IL-7, IL-17, IL-22, epidermal growth factor (EGF), transforming growth factor β1 (TGF-β1) in colonic homogenate of mice. Results: Olsalazine significantly increased the contents of IL-2, IL-10, IL-22, TGF and EGF in ulcerative colitis rats, and significantly decreased the scores of DAI, CMDI, HS and the contents in IL-7, IL-17, TNF-α, IL-1β and IFN-γ when compared with the model group. It improved the degree of colonic lesion in ulcerative colitis mice. Conclusions: It was suggested that olsalazine has a therapeutic effect on ulcerative colitis induced by DSS in mice, and the mechanism may be related to the increase of IL-2, IL-10, IL-22, TGF, and EGF and the decrease of the expression of IL-7, IL-17, TNF-α, IL-1β, and IFN-γ. Purpose (DSS BALBc BALB c Methods 3 w/v wv w v (w/v days 0.6 06 0 6 (0. g·kg1 gkg1 gkg g·kg 1 g kg g·kg-1 DAI , (DAI) CMDI (CMDI) HS, (HS) IL2, IL2 IL 2, 2 (IL)-2 IL10, IL10 10, 10 IL-10 factorα α TNFα, TNFα TNF (TNF-α) interferonγ interferon γ IFNγ, IFNγ IFN (IFN-γ) IL1β ILβ 1β β IL7, IL7 7, 7 IL-7 IL17, IL17 17, 17 IL-17 IL22, IL22 22, 22 IL-22 EGF, (EGF) TGFβ1 TGFβ (TGF-β1 Results IL-2 rats α, TNF-α group Conclusions IL1β, 1β, IFNγ. γ. 0. (0 kg1 g·kg- (DAI (CMDI (HS (IL)- IL1 IL-1 (TNF-α (IFN-γ IL- (EGF (TGF-β ( (IL) (IL