Bulinus truncatus snail is the intermediate host of Schistosoma haematobium, which causes serious damage to the urinary system of infected patients. To control it in its rapid interruption and/or elimination of the disease transmission would be efficient. Copper chlorophyllin (Cu-chl) and magnesium chlorophyllin (Mg-chl); two photosensitizers used in several biological applications, were bio-assayed against B. truncatus snails.  Mg-chl proved to be more toxic to the snails than Cu-chl; their LC₉₀ values were 516.7 and 668.9 ppm, respectively. The sub lethal concentrations of each photosensitizer significantly suppressed the fecundity (Mx) and reproductive rate (R₀) of treated snails, which could be partially attributed to the recorded disturbances in their biochemical parameters. The reduction rates of R₀ for snails treated with LC₂₅ Mg-chl and Cu-chl were 83.5% and 50.8%, respectively. Moreover, these photosensitizers exerted marked histological changes in the hermaphrodite gland of treated snails where spermatogonia and oogonia in the gland acini were degenerated, while the connective tissue was disintegrated. Both Mg-chl and Cu-chl exhibited toxic effect on B. truncatus snail and interfered with the biological parameters of it that could negatively interrupt the transmission of S. haemeatobium. Therefore, both chemicals could be considered in the control program of this parasite being cheap and environmentally safe.