The level of lipid peroxidation reflects the degree of free radical-induced oxidative damage in brain tissue of the elderly. We examined the effects of Manda, a product prepared by yeast fermentation of several fruits and black sugar, on lipid peroxidation in the senescent rat brain as model of aging. Senescent rats were provided with a diet containing 50 g/100 g Manda for 8 days, supplemented on day 8 with an intragastric administration of Manda (6.0 g/kg body wt.) twice daily. The hydroxyl radical scavenging activity was generated by the FeSO4-H2O2 system and analyzed by electron spin resonance spectrometry. Using this method, the addition of Manda (2.88 mg/ml) to brain homogenates of adult rats (0.06 mg/ml) had an additive inhibitory effect on lipid peroxidation compared with control adult rats not treated with Manda. Incubation of brain homogenates with Manda for 2 h and 3 h, significantly inhibited the increase in lipid peroxides (malondialdehydes and 4-hydroxyalkenals) levels in aged rats due to auto-oxidation. In addition, oral administration of Manda significantly suppressed the age-related increase in lipid peroxidation in the hippocampus and striatum, although such change was not observed in the cerebral cortex. Although Manda contains trace level of alpha-tocopherol, the level of alpha-tocopherol in Manda did no correlate with its antioxidant effect. Our results suggest that Manda protects against age-dependent oxidative neuronal damage caused by oxidative stress and that this protective effect may be due, in part, to its scavenging activity against free radicals.