This overview of pediatric diarrheal disease presents information on mortality, diarrhea and socioeconomic development, enteropathogen microbes, clinical features, nutritional sequelae, and preventive interventions. Differences in mortality rates between developed and developing countries may be more than 500 times for infant mortality due to gastroenteritis and 300 times for preschool children. Socioeconomic development influences the number of diarrheal episodes/child/year as well as clinical aspects related to etiology, severity, and nutritional sequelae. Diarrheal episodes are more severe in developing countries, their duration is longer, and dehydration is more likely to be a life-threatening complication. Of the major public health problems in developing countries, mortality in children under 5 years of age due to diarrhea is one of the most amenable to control measures. Oral rehydration, coupled with early restoration of foods and continuity of breast feeding, is the major strategy for diarrhea management. Antimicrobial preparations have not been effective, and uncoordinated programs aimed at providing latrines, water supplies, vaccination, economic development, or health education have produced disappointing results. Other public health interventions of proven efficacy include personal hygiene, avoidance of "night soil" as fertilizer, hygienic preparation of milk formula gruels for infants, sanitary food control, measles vaccination, vaccines of enteropathogenic microbes, and public health services improvement. In general, strategies based on socioeconomic development imply investments that are not feasible for the majority of countries with current high attack rates of diarrhea.