Fifty patients treated with intravenous hyperalimentation were observed while receiving from 1200-4800 kcal per day via a central venous catheter. They were observed while receiving only intravenous nutrition and also while receiving nutrition by mouth as well as by vein. Assessment of degree of hunger and satiety were made and compared with records of body weight, temperature, blood sugar level, and amount and duration of intravenous nutrients. Most patients reported hunger during therapy in spite of the intravenous calories. The onset of satiety was hastened by the intravenous nutrients and although patients would report mild to ravenous hunger while on intravenous nutrients alone, they were able to eat only small amounts of food when oral feeding was initiated. Four patients received intravenous fat emulsions in addition to the carbohydrate-amino acid solution. These patients did not experience hunger during the 24-hr period after fat administration.