In an in vivo Wistar albino rat model of experimental inflammatory bowel disease (IBD) induced by trinitrobenzene sulfonic acid (TNBS), elevated disease activity levels and indices of oxidative stress, inflammation markers, along with increased immunoreactivities of NF-κB and c-Jun N-terminal mitogen-activated protein kinase were observed in the colons of the TNBS colitis group. This evidence concerns the gene JUN and inflammatory bowel disease.