Mice genetically deficient in IL-25 are partially protected from chronic dextran sulfate sodium (DSS)-induced colitis. Mice were exposed to three cycles of DSS treatment. Each cycle of DSS involved seven days of DSS followed by 14 days on regular water. Mice were euthanized at the eighth day of the third DSS cycle. (A) Body weight change expressed as the percentage of initial body weight at day 0; (B) Clinical disease activity based on stool consistency (0–3), presence of blood in stool (0–2), and general appearance (0–2); (C) Colon length at euthanasia; (D) Representative H&E-stained colon sections (100X) and the histological activity index from a total score of epithelial damage (0–4) and inflammatory cell infiltration (0–4). Data are mean ± SEM and are representatives of two independent experiments with five or six mice per group. *P < 0.05 versus the respective WT.