Acute diarrhea is a leading cause of childhood morbidity and mortality. Primary care physicians and pediatricians should be familiar with its clinical features and management. Rehydration and maintenance of proper fluid and electrolyte balance are the most important aspects of treatment. While intravenous rehydration is the best form of treatment for children who are in shock or unable to drink, oral rehydration is the treatment of choice for the majority of children who have mild to moderate dehydration. Oral rehydration therapy is simple, practical, inexpensive, effective, and safe for children in developing as well as developed countries. We recommend the use of commercially available rather than homemade solutions. Antibiotic and antidiarrheal agents are usually not indicated. Early reintroduction of milk, formula, or solid food is important, as is instruction of parents in measures to minimize transmission of infectious agents.