Numerous probiotic agents have been studied for the management of diarrheal disease. In particular, the prevention and management of acute viral diarrhea, the treatment of recurrent Clostridium difficile diarrhea, as well as the control of antibiotic-associated diarrhea seem to be areas of significant potential benefit. A few agents, including Lactobacillus GG, Lactobacillus reuteri, and Saccharomyces boulardii, seem to be promising agents for the amelioration of the course of acute diarrhea in children when used therapeutically. The use of other agents, particularly Bifidobacteria, supplementing the regular feed of infants may have an effect as prophylactic agents against acute diarrheal diseases. In general, in pediatric populations, the effect of probiotic agents appears to be most significant against viral (rotaviral) diarrhea, suggesting that an immunological mechanism is responsible for the beneficial effects. The numerous agents, doses, and populations used make generalization difficult. Nevertheless, it is clear probiotic agents are becoming an important part of the armamentarium against gastrointestinal problems in infants and children.