Fecal microbiota(St. Jude Children's Research Hospital)

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.