Conditions such as poverty, underdevelopment, and lack of education facilitate the widespread transmission of the pathogens that cause diarrheal disease, dysentery, and enteric fever in young children. Such infections produce high rates of morbidity, mortality, and adverse nutritional consequences in the first 2 years of life. Although rapid socioeconomic development has produced a precipitous decline in mortality due to diarrheal disease in the developed world, such a trend is not likely in developing countries unless alternative measures are pursued. Nonspecific interventions pursued have included oral rehydration therapy to prevent and treat dehydration, promotion of breast feeding, health education to teach maternal technology, and early realimentation to diminish the nutritional consequences of infant diarrhea. In addition, there is reason to be optimistic about the future development of various immunizing agents against the major enteric pathogens. Epidemiologic data support the conclusion that prior natural infection with enterotoxigenic E. coli, Shigella, rotavirus, and V. cholerae OL confers protective immunity. Among the divergent approaches being followed in the development of vaccines against rotavirus are: 1) use of animal rotavirus as possible attenuated strains; 2) attenuating human rotaviruses by passage in tissue culture; 3) development of hybrid reassortant strains by coinfecting tissue cultures with both an animal strain well adapted to tissue culture and a human strain and then selecting a hybrid virus that possesses the human virus neutralization antigen but grows to higher titre in tissue culture; 4) evaluation of rotaviruses isolated from asymptomatic infected neonates in nursery outbreaks for their safety, infectivity, and immunogenicity in older children; 5) cloning a DNA copy of the RNA genus responsible for the neutralization antigens of rotaviruses; and 6) preparation of a synthetic peptide of the critical epitope of the neutralization antigen.