CXCL9 and colitis: Iron overload is well‐known to increase the production of inflammatory cytokines in macrophages[2, 7] and worsen colitis.[8] Contrarily, iron chelation reduced the severity of intestinal inflammation.[9] Through performing a cytokine array, butyrate was found to suppress the production of several pro‐inflammatory cytokines including IL‐1β, TNF‐α, CXCL9, and CCL11, whereas upregulated the levels of anti‐inflammatory cytokines such as IL‐13 and CX3CL1 (Figure 5A).