Both psoriasis and inflammatory bowel disease (IBD) are immunomediated diseases. Some of their therapeutic tools are monoclonal antibodies. Ixekizumab is an interleukin-17 (IL-17) inhibitor approved for the treatment of psoriasis. Cases of IBD onset have been reported in patients treated with this drug. We present the case of a 35-year-old patient with the onset of ulcerative colitis (UC) type of IBD after starting ixekizumab treatment.