There was little or no improvement in the median survival times of Drosophila melanogaster fruit flies when fed high concentrations of the singlet oxygen quenchers, beta-carotene and 1,4-diazabicyclo(2.2.2)octane. Singlet oxygen was presumably generated endogenously by inactivating catalse with 3-amino-1,2,4-triazole and feeding NaOCl. This treatment caused reduction in median life span of from 14.3 to 25% depending upon the NaOCl concentration used. beta-Carotene and 1,4-diazabicyclo(2.2.2)octane gave partial protection against the singlet oxygen generated by NaOCl. These data are interpreted to mean that normally occurring singlet oxygen does not contribute to senescence in Drosophila but that artificially produced singlet oxygen accelerates the rate of aging.