New pathogens that cause gastroenteritis in children are being recognized. Even well-recognized pathogens, such as Clostridium difficile, may require more extensive testing than was previously thought necessary. Several new tests have emerged that allow for faster identification of these pathogens so that same-day results may be possible. Probiotic therapy has emerged as a novel strategy for the treatment of gastroenteritis. New vaccines against both viral and bacterial causes of gastroenteritis are being developed. The most exciting recent advance in vaccine development may be the creation of edible vaccines. (C) 2000 Lippincott Williams and Wilkins, Inc.