Glycerol, a widely distributed constituent of food and an additive used in cigarette manufacture, has been tested for genotoxic potential in a battery of short-term genotoxicity assays. Glycerol was evaluated in the Ames Salmonella typhimurium mutagenesis assay (strains TA98, TA100, TA1535, TA1537 and TA1538), in the rat hepatocyte unscheduled DNA synthesis assay, in the Chinese hamster ovary (CHO) chromosome aberration assay, the CHO sister chromatid exchange assay and the CHO mammalian mutagenesis assay. All assays (except the rat hepatocyte unscheduled DNA synthesis assay) were conducted both with and without the addition of Aroclor-induced rat liver S-9. The results of all tests were negative, showing that neither glycerol nor its metabolites have genotoxic activity in the battery of tests used.