Lu-Duo-Wei capsule is a product of Chinese medicine having high efficacy in scavenging superoxide and hydroxyl radicals. It contains antioxidants, which may increase longevity, but whether Lu-Duo-Wei capsule has such an effect is unknown. In this study, supplementing the basic diet with Lu-Duo-Wei resulted in prolonging the life span of houseflies and fruit flies. Moreover, the effect of prolonging the life span of houseflies by Lu-Duo-Wei was significantly higher than that of tea polyphenol. The result not only confirms our previous report but also supports the free radical theory of aging.