While conditional deletion of EP4 receptors in T‐cells ameliorated T‐cell‐mediated chronic colitis accompanied by reduction in Th1 accumulation in the colon (Yao et al., 2013), the administration of PGE2 or misoprostol, an EP3/EP4 receptor agonist, augmented 2,4,6‐trinitrobenzene sulfonic acid‐induced colitis with an increase in IL‐17 and IL‐23 levels in inflamed colon (Sheibanie et al., 2007b). The gene discussed is IL17A; the disease is colitis.