Diarrheal diseases due to infection constitute a major burden of disease. Dehydration resulting from diarrhea can be fatal. It is the cause of approximately 1.8 million deaths every year. The vast majority of these deaths are of children under five years of age living in low- and middle- income countries. Interventions to prevent diarrhea include provision of safe water, hand washing, the use of sanitation facilities, exclusive breastfeeding of infants and rotavirus vaccination. Diagnosis is guided by symptoms into one of three categories: acute watery diarrhea, dysentery or bloody diarrhea, or persistent diarrhea of longer than 2 weeks in duration. Treatment of diarrhea in children includes oral rehydration with a pre-formulated solution or with fluids that can be prepared and administered in the home. Zinc supplementation is recommended. Only in certain circumstances are antibiotics advised and anti-motility agents are discouraged. The lives of many children could be saved with proper case management of diarrhea. With immediate and sustained actions to decrease both the incidence and mortality attributed to diarrhea, the burden of this prominent public health threat could be dramatically reduced.