Protection against C. rodentium is known to require IL-17a and IL-17f (Ishigame et al., 2009; Collins et al., 2014b), however, IL-17f-deficient mice are resistant to dextran sodium sulfate (DSS)-induced colitis, presenting milder acute intestinal inflammation (Leppkes et al., 2009; Tang et al., 2018). Here, IL17F is linked to colitis.