This section contains timely reviews of three topical subjects. The use of probiotics to prevent Clostridium difficile infection (CDI) is a controversial area, with conflicting data, and a paucity of robust, controlled, appropriately powered, clinical trials to provide a clear picture. Mills et al. examine the evidence for the use of probiotics, including recent clinical trial data and new approaches to microorganism-based therapy for CDI. A new systematic review and meta-analysis concluded that probiotic use may reduce the rate of CDI in high-risk populations by as much as 50% . Nevertheless, prior clinical trials, and indeed meta-analyses have yielded conflicting results [3–5]. Notably, meta-analyses of the efficacy of probiotics aggregate data from studies employing different microorganisms, formulations and dosages. Furthermore, individual study deficiencies, including some that have high influence on the conclusions of the reviews , are often not addressed. Lastly, the largest randomized controlled trial of a probiotic combination product of lactobacilli and bifidobacteria showed no benefit in the prevention of C. difficile infection .