Black tea extract (BTE) is a mixture of epicatechins and theaflavins. The present study investigated the effect of BTE on the lifespan of Drosophila melanogaster. Results showed the mean lifespan was significantly extended from 51 to 56days upon BTE treatment. Gene expression of superoxide dismutase (SOD1 and SOD2), catalase (CAT), and methuselah (MTH) was characterized by an increase in young and then a decrease in aged fruit flies. Higher gene expression of SOD1 and CAT was observed in the BTE-treated group than the control flies. However, BTE exerted a minimal effect on the expression of SOD2 and MTH genes. Dietary fat could induce oxidative stress and shorten the maximum lifespan to 15days, while addition of 10mg/ml BTE into diet extended it to 28days. Paraquat and H(2)O(2) challenge tests demonstrated that BTE prolonged the survival time only for Oregon-R wild type flies but not for SOD(n108) or Cat(n1) mutants. This suggests that the lifespan-prolonging activity of BTE is mediated at least in part through SOD and CAT.