Findings were validated with targeted Trp metabolomics in experimental colitis and in vitro in fibroblasts, intestinal epithelial cells (IECs), and peripheral blood mononuclear cells (PBMCs).<h4>Results</h4>Active IBD is marked by enhanced Trp degradation driven by inflammatory cytokines through the JAK/STAT pathway. The gene discussed is SOAT1; the disease is inflammatory bowel disease.