Primarily occurring in infants less than three months of age, it is associated with significant weight loss and intestinal malabsorption. Chronic infant diarrhea often is unresponsive to either antibiotic therapy or formula changes. Simple diarrhea that is not cured promptly may set in motion a vicious cycle of physiological processes which perpetuates the diarrhea. As time passes it becomes increasingly difficult to correct the underlying cause. Any one of five broad mechanisms may be responsible for inducing chronic infant diarrhea: