Participants will be eligible to receive an FMT on or after Day +30 post-HCT. FMT will be performed using FMP material obtained from OpenBiome. 60 mL of FMP will be administered via NJ tube and 250 mL via colonoscopy. A second FMT may be performed at least 14 days after the initial FMT in GI clinical symptoms have partially improved or have not changed. The second FMT will be administered using the same procedure as in the initial FMT
The study participant is being asked to take part in this clinical trial, a type of research study, because the participant has Gastrointestinal (GI) symptoms following a Hematopoietic Cell Transplant (HCT).~Primary Objective~To determine the safety and feasibility of FMT for treating a GvHD of the gut following HCT.~To determine the safety and feasibility of FMT for treating HCT induced gut dysfunction.~Secondary Objectives~To assess the potential efficacy of FMT for treating a GvHD of the gut following HCT.~To assess the potential efficacy of FMT for treating HCT induced gut dysfunction.