Patients who are on antibiotics showed a decrease in antibiotic associated symptoms after taking probiotics. This study looked at the effectiveness of probiotics (live bacteria that can take up residence in digestive tracts) in treating common side effects of antibiotics such as antibiotic-associated diarrhea and life-threatening side effects such as Clostridium difficile infection. These two conditions are associated with high morbidity, mortality, and health care costs. Antibiotics are non-specific in how they target both our good and bad bacteria. Good bacteria can be killed off that protect us from pathogens like Clostridium difficile, a bacterium that can cause symptoms ranging from diarrhea to life-threatening inflammation of the body. St. Michael’s Hospital, June 2013