Essential fatty acid deficiency is a common finding in patients nourished parenterally with hypertonic glucose and amino acids. In this study, we measured the linoleate concentration in the livers of 3 groups of patients. All the patients had operable upper gastrointestinal tract malignancies. Group I ate the hospital's regular diet ad libitum. Group II were given total parenteral nutrition (TPN), Group III received both enteral and parenteral nutrition and obtained about 35% of their caloric intake from food. The percentage of total liver fatty acids as linoleate were group I, 15.2 +/- 1.2%, group II, 3.7 +/- 1.4%, and group III, 2.8 +/- 1.6%. Data are expressed as the mean +/- 1 SEM. The patients who received 35% of their calories by mouth as food and the patients on TPN were found to be equally depleted in linoleate.