There is a general agreement that maintenance of long term potentiation (LTP) is markedly impaired with age (3). The impairment in LTP in aged rats was associated with an increase in accumulation of reactive oxygen species (ROS) that appears to be due to an increase in superoxide dismutase (SOD) activity in the absence of concomitant changes in activities of glutathione peroxidase or catalase (3). Diet supplements with antioxidants can reverse age-impaired ability to sustain long term LTP. There is evidence that natural antioxidants from fresh fruit could be more effective than a dietary supplement (5). An apple of the variety annurca is a typical product cultivated in the area around Naples and it has been previously characterized for a high antioxidant power (1,2). The aim of the present work was to study the effects of annurca apple in young and old rats on LTP induced in the dentate gyrus. Furthermore we studied the effect of this diet on the activity of superoxide dismutase on frozen brain sections (4). Groups of aged and young rats were fed with a control diet or a diet supplemented with fresh apple of the annurca variety for 10 weeks. After this period, rats were anaesthetized with intraperitoneal injection of urethane (1.0 g/kg) and assessed for the ability to sustain LTP. The responses were quantified by the analysis of fEPSP slope expressed as a percentage of the pre-tetanus mean value. At 50 min after high frequency stimulation, the mean value of fEPSP ± SEM was 129.8 ± 5.3 for the aged treated group, 112.0 ± 1.7 for the aged control group, 129.8 ± 6.2 for the young treated group and 124.8 ± 2.1 for the young control group. One-way analysis of variance showed significant differences among the groups. Post hoc test analysis showed that fEPSP in the aged control group was significantly smaller than the other groups. Therefore, aged rats fed with the supplemented diet sustained LTP at the level of young rats. An age-related increase in SOD activity, quantified by histochemical method, was also reversed by the apple-supplemented diet. This result demonstrates that annurca apple in the diet could have an important health care role in aging. All animals were humanely killed at the end of the experiment.