Bulinus truncatussnail is one of the most medically important snails.The goal of this study was to evaluate the molluscicidal effect of saponin on these snails and study how it affects their biological functions. The present results showed that saponin had a molluscicidal activity against adultB. truncatussnails after 24h and 72h with LC50(57.5 and 27.1 ppm, respectively) and had ovicidal acivity on the snails’ embryos. By studying the effect of the sublethal concentrations (LC1048.63 ppm or LC2552.83 ppm) exposure onB. truncatussnails, they resulted in significant decreases in the survivorship, egg-laying, and the reproductive rate compared to untreated snails. Both concentrations caused morphological changes to the snails’ hemocytes, where, after the exposure, granulocytes and hyalinocytes had irregular outer cell membrane and some cell formed pseudopodia. Granulocytes had large number of granules, vacuoles, while hyalinocytes’ nucleus was shrunken. Also, these concentrations resulted in significant increases in sex hormone levels (17β-estradiol and testosterone) in tissue homogenate ofB. truncatussnails. It resulted in significant decrease in total antioxidant (TAO) activity, while, significantly increased lipid peroxidase (LPO) level, superoxide dismutase (SOD), nitrogen oxide (NO), and glutathione-S-transferase (GST) as compared to control group. Histopathological and genotoxicological damages occurred in snails’ tissue after exposure to these concentrations. Conclusion, saponin has a molluscicidal effect onB. truncatussnails and might be used for the control ofschistosomiasis haematobium.Besides, these snails could be used as invertebrate models to reflect the toxic effects of saponin in the aquatic ecosystem.Graphical Abstract