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

The data being measured for this study include: Primary outcome = incidence of diarrhea during and after treatment with antibiotics. An episode of diarrhea is defined as the discrete period between the time when stool output meets or exceeds three soft and unformed or watery bowel movements to the time when formed stools return, which must be at least 48 hours later. Secondary variables: 1. severity of diarrhea measured as the discrete period between the time when stool output meets or exceeds 3 soft and unformed or watery bowel movements to the time when formed stools return. 2. frequency of stool samples positive for C. Difficile toxin A or B at baseline, when presenting with diarrhea during the study period, and at the follow-up 21 days post-antibiotic-treatment to detect possible clearance of C. Difficile, in patients ingesting L. reuteri versus placebo. 3. frequencies of other gastrointestinal symptoms at 1, 2, and 4 weeks, in the L. reuteri group versus placebo and assessed by the validated Gastrointestinal Symptom Rating Score.