Visit 1 - screening visit: This visit will take about 1 hour. The study doctor will talk to the patient about C-diff infection and fecal transplant in detail. Investigators will ask you questions about your medical history and health. A complete physical examination will be done. Investigators will order a pregnancy test (for girls who are old enough to become pregnant) and take blood (about 1.5 teaspoons) to make sure you do not have any other illness or infections (other than C-diff.) If the pregnancy test comes back positive on a patient who is younger than age 18, both the patient and parent(s) will be informed. The study doctor will then choose a possible stool donor. The study doctor will ask the donor to fill out a questionnaire about their medical history, past and present diseases, allergies and medications. If this donor seems suitable, blood and stool tests will be performed on the donor.