Intriguingly, several previous reports have found that a high abundance of butyrate‐ or SCFA‐producing bacteria was associated with better responsiveness to anti‐TNF‐α (αTNF‐α) therapy in IBD patients.[13] This prompts us to investigate whether macrophage iron metabolism could affect the therapeutic efficacy of TNF‐α blockade. Here, TNF is linked to inflammatory bowel disease.