Diarrheal disease, which is most often caused by infectious pathogens, is a significant cause of morbidity and mortality worldwide, especially in children. This is particularly true in developing countries. Recent outbreaks of infectious diarrhea in developed countries, including the USA, are often attributed to food handling and distribution practices and highlight the need for continued vigilance in this area. Another common cause of infectious diarrhea, Clostridium difficile infection (CDI), has historically been associated with the use of antibiotics and exposure to a health-care setting but is now increasingly common in the community in persons who lack the typical risk factors. Recent scientific advances have also led to new and proposed new therapies for infectious diarrhea, including fecal microbiota transplant (FMT) for recurrent C. difficile infection (RCDI), probiotics for prevention of antibiotic-associated diarrhea (AAD) and CDI, and the use of zinc supplementation in the treatment of acute diarrhea in children. Other therapies that have been in use for decades, such as the oral rehydration solution (ORS), continue to be the targets of scientific advancement in an effort to improve delivery and efficacy. Finally, post-infectious irritable bowel syndrome (PI-IBS) is an increasingly recognized occurrence. Attempts to understand the mechanism behind this phenomenon are underway and may provide insight into potential treatment options. © 2014, Springer Science+Business Media New York.