Lactobacillus GG, a nonpathogenic microorganism, will be administered in this study. A dose of 1010 colony factor units (cfu) twice daily will be given to the experimental group (n =47). The control group will receive a placebo (n = 47) that will be identical in appearance to the probiotic. All supplements will be administered orally or via feeding tube. The study endpoint will be 10 days after antibiotic use is discontinued or patient discharge Parameters measured will include 1) the occurrence of pneumonia or infection in the wound, blood, or urine, as defined by The National Nosocomial Infection Surveillance System (A localized or systemic condition that results from adverse reaction to the presence of an infectious agent(s) or toxin(s)) and clarified by the Infection Control Nurse, 2) incidence of diarrhea defined as 3 or more loose or watery stools per 24 hours, 3) weekly weights and labs (including total protein, albumin, prealbumin and C-reactive protein) as obtained per routine care, 4) length of antibiotic use, 5) length of stay.