A review of data on the morbidity and mortality caused by persistent diarrhea (more than 14 days' duration) was undertaken from studies in several geographic areas, including Bangladesh, Brazil, Ethiopia, India, Indonesia, and Peru, over the last 3 decades. An estimated 3-5 billion diarrheal illnesses and 5-10 million diarrhea-related deaths occur annually among 3 billion people in Africa, Asia, and Latin America. Mostly the 338 million to 1 billion episodes and 4.6 million deaths annually. A study from India showed that the incidence of persistent diarrhea was greater in the age group 0-11 months (31 episodes/100 child-years) than at age 12-23 months (9 episodes/100 child years) or 24-35 months (6 episodes/100 child-year). Similar results were obtained in periurban Peru, periurban northeastern Brazil, and rural guatemala. Diarrhea is believed to precipitate and exacerbate malnutrition while malnutrition predisposes to diarrhea. 2 studies in both Bangladesh and Peru indicate that the risk of developing diarrhea inversely parallels delayed-type hypersensitivity reactions to standard skin-test antigens. In a cohort of 175 children under 5 years of age over a 28-month period in an urban slum in northeastern Brazil the children had an average of 11 episodes/year and spent 82 days/year with diarrhea. The leading potential pathogens seen with persistent diarrhea in some areas are enteroaggregative E. coli and Cryptosporidium. Other pathogens include Shigella, Salmonella, enteropathogenic (LA (local)) E. coli, and variably Giardia lamblia. Recent nutritional management promotes breast feeding, dietary supplementation with vitamin A, zinc, iron, folate, and vitamin B 12, and improved oral rehydration solutions with glucose polymers (such as rice starch) and possibly neutral amino acids (such as alanine or glycine) and glutamine.