RecruitingPhase 1ProcedureFecal Microbiota Transplant and Dietary Fiber Supplementation for the Treatment of Gut Graft Versus Host DiseaseThis phase I trial studies how well fecal microbiota transplant and dietary fiber supplementation work in treating patients with gut graft versus host disease. Fecal microbiota transplant entails inoculating donor stool into a recipient's gastrointestinal tract. Changing the gut microbiome by fecal microbiota transplant and fiber supplementation may help treat gut graft versus host disease.