1) Background: We analyzed, by PET-SCAN, how growth hormone (GH) might act on the brain of a not GH-deficient elder woman who suspected that she was developing Alzheimer's disease; 2) Methods: After performing a first psychometric study (TAVEC verbal learning test), the metabolic activity of brain structures related to cognition, memory and behavior was analyzed by 18-F Fluorodeoxyglucose PET-SCAN. The patient was then treated with GH (0.4 mg/day) during three weeks and the last day under this treatment a new PET-SCAN was carried out. One month after commencing the treatment with GH a new TAVEC test was performed; 3) Results: GH administration normalized the cognitive deficits observed in the first cognitive test and significantly (p < 0.025) increased (Voxel-Based Morphometry) the metabolic activity in the left hippocampus, left amygdala and left parahippocampus, but also in practically all brain cortical areas; 4) Conclusions: This is the first study in which the effects of GH on the brain have been visualized in images. Our data confirm the positive effects of this hormone on cognition and memories; although they do not allow us to conclude whether GH administration may be useful in the early stages of Alzheimer's disease, they seem to be promising.