rehydration solution (ors), recommended by both aap and the world health organization (who), must be composed of 50-90meq/l sodium and 2% glucose or other complex carbohydrates. ors is easily found in the us because it is available without a prescription. the typical amount of ors administered is 50ml/kg over a 4-hour time period for mild dehydration and 100ml/kg over a 4-hour time period for moderate dehydration with an extra 10ml/kg for every loose stool. repeat this administration regimen for as long as the signs and symptoms of dehydration continue. it is important to take measures early on to maintain hydration. along with ort, who recommends a 10-14 day course of 20 mg zinc tablet supplementation, stating it will shorten the length of diarrhea and potentially improving harmful outcomes. the niddk recommends a visit to the doctor when a child experiences stools containing pus or blood (black, tarry, or coffee ground-like appearance), signs of dehydration, diarrhea longer than 24 hours, or a fever of 102 degrees or more. epidemiology diarrheal illness in children accounts for 1.5 to 2.5 million deaths per year worldwide. it is responsible for the secondary cause of mortality among children less than 5 years of age surpassing the combined childhood deaths from malaria, measles, and aids. in 2009, the world health organization (who)/united nations international children's emergency fund (unicef) reported 2.5 billion cases of diarrhea in children less than 5 years old. more than half of the cases occurred in africa and south asia. it is estimated that africa and south asia comprise more than 80% of deaths from diarrhea in children. in fact, about 75% of the childhood deaths from diarrhea come from only 15 countries. according to the world health organization (who), the proportion of deaths attributable to diarrheal illness among children less than 5 years of age was 13.2% in 2002. half of these childhood deaths were due to chronic diarrheal causes. worldwide, studies estimate that diarrheal illness affects 3 to 20% of children under the age of 5 with an incidence of 2.7 episodes of diarrhea per child-year. developing nations experience higher burden of disease and mortality from chronic diarrhea in children compared to developed nations. in the united states, it is reported that 15 to 20% of young children have an episode of acute diarrhea each year. compared to worldwide estimates, the united states has a lower incidence rate of chronic diarrhea in young children reported at 0.18 episodes per child year. in pediatrics, diarrhea is a common complaint making up 9% of u.s. hospital visits for children less than 5 years old. in contrast to resource-poor nations, resource-rich nations such as the united states experience less chronic diarrhea severity. in the united states, approximately a quarter of chronic diarrhea cases in young children seek medical care and less than 1% of cases are hospitalized.