Clostridium difficile colitis infection is an opportunistic infection with as high as an estimated 30,000 deaths and 4.8 million dollars in healthcare costs recorded in 2011. The most common risk factor for infection is antibiotic therapy. Studies reviewed consisting of a meta-analysis of 19 randomized clinical trials demonstrate a beneficial effect of probiotics in preventing CDCI with the highest efficacy noted when initiated within 2 days of antibiotics. However, variations in dosing, initiation and species of probiotic have unknown effects in study results. The most significant correlation noted was the decreased incidence of CDCI by almost 50% when adjusting for timing of probiotic administration nearer to the first dose of antibiotics. The adverse effects of probiotics across studies were similar when comparing control and experimental groups.