Fecal microbiota transplantation (FMT) is the transfer of stool from a healthy donor into the colon of a patient whose disease is a result of an altered microbiome, with the goal of restoring the normal microbiota and thus curing the disease. The most effective and well-studied indication for FMT is recurrent Clostridium difficile infection. At this time, there is insufficient evidence to recommend FMT for other gastrointestinal diseases, but studies are under way. There is also insufficient evidence to recommend FMT for nongastrointestinal diseases at this time. The field is rapidly emerging.