All hospitalized patients except infants (a total of 1,647 patients) who received central venous TPN solutions at UCDMC from 1981 through 1985 were studied to determine the incidence of complications from the use of TPN. A complication was considered to have occurred if the patient experienced obvious morbidity, mortality, or both; an event known to be deleterious, despite a lack of demonstrable morbidity; or premature loss of the central venous catheter. Complications related to catheter placement occurred in 5.7 percent of patients, sepsis in 6.5 percent, mechanical complications in 9 percent, and metabolic complications in 7.7 percent. The incidence of induction of sepsis increased during 1984 to 1985 due to the introduction of multilumen central venous catheters. The most frequent catheter placement complications were hemorrhage and pneumothorax. Major venous thrombosis and nursing mishaps were the most common mechanical complications. Metabolic complications were infrequent and were generally not severe after adjustment of the protocol in late 1981. Four patients (0.2 percent) died from TPN-associated complications: a child on home TPN who underwent a catheter change and in whom hyperosmolar hyperglycemic coma developed, a patient with end-stage chronic obstructive pulmonary disease in whom tension pneumothorax occurred, a patient who died from complications of subclavian artery laceration, and a patient who died from Candida septicemia. Complications of TPN are frequent and may be severe. Quality assurance mechanisms for identification of these complications are necessary and should form the basis for the establishment of appropriate protocols.