Fù zi and gān jiāng significantly ameliorated the clinical symptoms of body weight loss, colonic shortening, increased DAI and splenomegaly, as well as histological scores of UC mice. IFN-γ, TNF-α, IL-1β, IL-6, IL-10 and IL-17A were suppressed. The levels of MPO, iNOS and COX-2 mRNA were suppressed too. The activation of MAPK, NF-κB and STAT3 signaling pathways were inhibited. The gene discussed is MPO; the disease is Splenomegaly.