Toxicity assessment of chemicals is crucial in determining safe levels for human exposure.Current in vivo rodent models of toxicity can no longer meet the increasing requirements of proper toxicological evaluation,and there is a critical need to develop more efficient techniques of toxicity screening.In vivo studies in non-rodent model organisms provide a novel platform for screening a large number of chemicals for reproductive toxicity.We performed a brood size assay after chemical exposure in the nematode Caenorhabditis elegans(C.elegans)to determine potential toxic effects of these chemicals on reproduction.Sixteen hydrosoluble chemicals were selected from the Globally Harmonized System of Classification and Labeling of Chemicals(GHS)that is a system for classifying chemicals and other dangerous goods.Young nematodes were exposed to various concentrations of chemicals for seven days and the total number of offspring produced per animal was determined,and.the no-observed-effect level(NOEL)and lowest-observed-effect level(LOEL)for reproductive toxicity were calculated..Our results indicate that GHS compounds classified as moderate to high toxicity causes a significant decrease in brood size.We also found a positive correlation between the NOELs or LOELs and the LC50s of C.elegans and the LC50s.Furthermore,the NOELs of C.elegans demonstrate a positive correlation with the rodent oral LD50s.Taken together,our studies indicate that C.elegans is a useful screening tool to complement other model systems in reproductive toxicological research.