The role of interleukin 25 (IL-25) in a number of human diseases still has not been extensively studied, here we attempt to evaluate the role of recombinant IL-25 (rIL-25) in the development of dextran sulfate sodium (DSS)induced experimental colitis. Acute colitis was induced in female C57BL/6 mice by oral administration of 2.5% DSS in drinking water ad libitum. At the same time as the start of DSS exposure, mice were injected intraperitoneally with 0.4 μg of rIL-25 or PBS. Then disease activity index (DAI), histological changes and survival rate were observed. The levels of IL-17, IL-23, and TGF-β1 in colon tissues were determined by ELISA, and the production of IL-17 by CD4+/CD8+ T cells was detected by intracellular flow cytometry. In contrast to the DSS treated mice, DSS + rIL-25 treated mice displayed a lower DAI, limited histological changes and prolonged survival. The levels of IL-23 and TGF-β1 were significantly elevated in the DSS + rIL-25 treated mice compared to the DSS treated mice. There was no significant difference in the production of IL-17 in colon tissues and CD4+/CD8+ T cells between the DSS + rIL-25 treated mice and DSS treated mice. Our findings suggest the role of IL-25 in inhibiting development and progression of acute colitis in DSS-induced mouse colitis model. Cellular & Molecular Immunology. 2008;5(6):425-431.