The effects of aged garlic extract (AGE), chronically administered in the diet, on longevity and spatial learning performances were studied using the senescence-accelerated mouse (SAM). A solid diet containing 2% AGE was given to senescence-accelerated-prone mouse 8 (SAMP8) and senescence-accelerated-resistant mouse 1 (SAMR1) from 2 months of age. The survival ratio of SAMP8, a substrain of senescence-accelerated-prone mouse, was significantly lower than that of SAMR1, a substrain of senescence-resistant mouse. In the SAMP8, administration of AGE perfectly prevented the decrease in survival ratio. Moreover, AGE markedly improved the learning deficits of SAMP8 in the Morris water maze test. These results suggest the possibility that AGE prevents physiological aging and age-related memory disorders in human.