Administration of cholecystokinin (CCK) reduces food intake in rats. This effect of CCK was attenuated in rats with thermal lesions of the area postrema. This result was specific to CCK, as area postrema lesions had no effect on the reduction in food intake produced by amphetamine. The effect of the lesions was not due to changes in taste sensation as the lesioned rats showed no deficits in morphine induced conditioned taste aversions. Thus, the area postrema may be the major site where CCK acts to decrease food intake.