Animal and human studies have suggested a satieting effect of ceruletide, an analog of cholecystokinin. In humans, signs of a selectively diminished central nervous processing of food stimuli may provide a more valid measure of satiety than overt eating behavior. To assess the satieting effects of ceruletide in humans, effects of ceruletide and food intake on memory of food stimuli and stimuli not related to food (neutral and sex) were compared with memory performance in fasted subjects. In experiment I, recall of slide-projected words was tested in 12 fasting men in a within-subject comparison (i) following intravenous administration of saline solution, (ii) of ceruletide (6.75 micrograms), and (iii) after having eaten a regular breakfast. The P3 component of the event-related potential to the stimuli was assessed as a physiological sign of memory processing. In experiment II, recognition of pictures was tested in a between-subject design in 36 fasting men following (i) administration of saline solution, (ii) of ceruletide (6 micrograms), and (iii) intake of an opulent meal. After food intake, recall and recognition of food and also of sex stimuli were diminished, but were increased for neutral stimuli. Ceruletide diminished recognition of food stimuli and increased that of neutral stimuli; similar effects on recall of food and neutral stimuli failed to reach significance. P3 amplitude did not reflect changes in memory performance. Memory of food stimuli declined after ceruletide as well as after food intake, suggesting ceruletide mediates satieting effects on memory processing.