In the U.S., children under five years of age experience 20-35 million episodes of diarrhea per year. These episodes lead to 2-3.5 million physician visits (which account for 10% of all visits by children), more than 200,000 hospitalizations (13% of hospital admissions in children under five years), and 325-425 deaths annually. In 1991, the outpatient costs of treating diarrhea in children under age three was calculated at 0.6-1 billion dollars per year.