RecruitingPhase 2Biological interventionFecal Microbiota Transplantation for IBSThe purpose of this study is to learn the efficacy and safety of fecal microbiota transplantation (FMT) using stool from a donor with low proteolytic activity and containing the bacteria Alistipes putredinis in patients with irritable bowel syndrome (IBS) and high proteolytic activity. Proteolytic activity is the breakdown of proteins into smaller polypeptides or amino acids.