OBJECTIVE To provide recent guidelines to reduce the incidence of diarrheal diseases. We discuss the definition, clinical aspects, pathophysiology, diagnosis, management, and prevention of persistent diarrhea. METHODS Electronic search of the MEDLINE database, Google search. RESULTS Acute diarrhea may be caused by a variety of agents, including bacterial, viral, and protozoan pathogens. The top priority in treatment of diarrhea is replacement of fluid and electrolytes losses, particularly at the acute stage, and, under certain circumstances, eradication of the enteropathogenic agent. On the other hand, treatment of persistent diarrhea should focus on prevention and management of food intolerance and malnutrition. CONCLUSIONS Promotion of breastfeeding, adequate interventions in the treatment of acute diarrheal episodes, introduction of safe dietary strategies for prevention of malnutrition, and improvements in sanitation and hygiene conditions, including sewage and clean water, are essential measures for the reduction of diarrheal morbidity and mortality rates in children under 5 years of age.