Although long associated with infectious diseases, malnutrition is recognized as a major effect of specific infections, especially those of the gastrointestinal tract. Synergistic exacerbation of infections and nutritional deficiency commonly begin with weaning, where the impact of repeated infections and possible monocyte mediator release may have an even greater effect on malnutrition of young children than that of deficient diets in many areas. Reviewed here are the detailed host alterations seen with specific enteric infections that lead to malnutrition. These include mucosal dysfunction, systemic metabolic responses, impaired intake, digestion and absorption, nutrient losses, altered immune responses, and ultimately, impaired growth, development, and nutrition. The tremendous health impact of diarrhea on both morbidity and mortality in many developing areas must be recognized and controlled along with correction of food shortages in order to improve the nutrition, growth, and survival of impoverished children.