Although it is generally accepted that the distal gut microbiota are relatively stable in healthy adult individuals, a collapse of the microbial community structure resulting from antibiotic therapy or pathogen presence can lead to gut dysfunction. However, recent findings demonstrate that it is possible to engraft new microbiota from a donor source, resulting in the restoration of gut functionality and improvement in health. This builds upon decades of case reports and series in which fecal transfers were used to successfully treat refractory and recurrent Clostridium difficile infection. As fecal transplantation becomes part of mainstream medicine, it will likely provide a unique opportunity to study the interactions of humans with their attendant microbiota and allow greater insights into their synergistic functionality.