Molluscicidal activity of different organic solvent extracts of latex of Euphorbia pulcherima and Euphorbia hirta (Family-Euphorbiaceae) against two freshwater harmful snails Lymnaea acuminata and Indoplanorbis exustus has been reported. Both the snails are the intermediate hosts of Fasciola hepatica and Fasciola gigantica, which cause endemic fascioliasis in cattle and livestock of Eastern part of India. Toxicity of all the extracts of both the plants was time as well as dose dependent against both the snails. There was significant negative correlation between LC values and exposure periods. Thus, the LC values of latex of Euphorbia pulcherima of chloroform and carbon tetrachloride extracts were decreased from 0.51 mg/L (24 h) to 0.24 mg/L (96 h) and 0.51 mg/L (24 h) to 0.21 mg/L (96 h) respectively, against Lymnaea acuminata and from 0.46 mg/L (24 h) to 0.11 mg/L (96 h) and 0.49 mg/L (24 h) to 0.17 mg/L (96 h) against Indoplanorbis exustus. Similar trend was also observed in case of Euphorbia hirta of all the solvent extracts. The doses that can be used for killing the 90% population of snail Lymnaea acuminata are safe for non-target fish Channa punctatus, which shares the habitat with these snails. We thus believe that further purification of active compounds present in Euphorbia pulcherima and Euphorbia hirta latex may eventually be of great value for the control of harmful snails and other aquatic pests.