Research in parenteral nutrition in infants has proceeded rapidly over the past few years, thanks in large part to the perfection of safe central venous delivery of hypertonic nutritive infusates. At present, there are clear definitions of indications and expectations of results for this method of therapy in two well-defined groups of patients-i.e., selected surgical neonates and infants with chronic intractable diarrhea. In addition, we have suggestive evidence of another potentially valuable application in the nutritional management of very low birthweight infants. However, in this group, a controlled study will be necessary before the role of total parenteral nutrition (TPN) in neonatal care of such infants can be determined precisely. Results obtained with TPN in adults with inflammatory bowel disease or acute renal failure suggest that trials of this technique in pediatric patients with these disorders should be carried out. As a result of the research in TPN carried out thus far, we have learned how to minimize or to treat many of the complications of the technique and we have identified at least the ways by which still others can be prevented. The future holds many new advances not only in the refinement of existing parenteral nutritional solutions but also, and perhaps of even greater importance, in the perfection of individualized total nutritional therapy for specific patients using the enteral route for those discrete components of intake for which digestive and/or absorptive mechanisms are unimpaired and using the parenteral route for the remainder.