Lactobacillus Reuteri in the Prevention of Antibiotic Associated-diarrhea and Clostridium Difficile

Inclusion Criteria: * Receiving antibiotics for not more than 48 hours prior to enrollment and free from diarrhea * able to understand and sign informed consent and HIPPA * available throughout the study period * subjects should have the mental ability to understand and willingness to fulfill all the details of the protocol Exclusion Criteria: * three or more soft and unformed or watery stools per day at admission * receiving chemotherapy or radiation therapy * diagnosis of inflammatory bowel disease * NPO without PO meds * neutropenia (an absolute neutrophil count (ANC) of less than 1500/microL) * HIV positive with a CD4+ T-lymphocyte count \<400 per mcL blood * requiring care in an intensive care unit * status-post bowel resection during hospitalization * patient's receiving antibiotics four weeks prior to hospitalization * patient with severe life threatening illness or immunocompromised * pregnancy