There has been an alarming increase in the incidence and severity of Clostridium difficile infection (CDI) in North America over the past decade. Relapsing infection is a common problem in patients treated for CDI, often requiring prolonged and expensive courses of oral vancomycin with limited alternative treatment options. This study will determine if fecal microbiota transplantation, which involves administering fecal flora from a healthy stool donor to a patient with relapsing CDI, is an effective and safe treatment.