Thirteen infants with intractable diarrhea were classified as having severe or moderate malabsorption on the basis of D-xylose absorption. Within each group (designated severe and moderate), patients were randomly assigned to continuous enteral nutrition (CEN) with an elemental formula or to an alternative therapy: total parenteral nutrition (TPN) for the severe patients or intermittent oral nutrition (ION) with the elemental formula for the moderate patients. Within the severe group, CEN and TPN produced similar correction of malnutrition (6.0 +/- 2.5 weeks vs 6.5 +/- 2.5 weeks for weight to reach the 5th percentile for age, P = 0.69), but CEN was associated with faster resolution of malabsorption and diarrhea (2.8 +/- 0.5 weeks vs 9.8 +/- 1.1 weeks, P = 0.02), fewer complications, and less expensive hospitalization than TPN. The moderate group was too small for clear distinctions between the two therapies. D-xylose absorption effectively distinguished between severe malabsorption (requiring 20.6 +/- 2.6 days of enteral therapy before tolerance of oral feeding) and moderate malabsorption (requiring 11.6 +/- 1.7 days), P less than 0.03. Enteral therapy is more widely applicable in severe intractable diarrhea of infancy than has been appreciated, and can produce superior results to TPN.