Fecal microbiota transplantation (FMT) is the delivery of stool from a healthy donor to a recipient with the goal of mitigating disease by modifying the structure and/or function of the gut microbiome. This shotgun approach has proven to be a highly effective therapeutic modality for recurrent Clostridium difficile infection (CDI).1,2 The availability of the therapeutic substrate (ie, stool), together with its ease of administration, has advanced the practice of gut microbiota manipulation in patients more rapidly than our scientific understanding.