Abstract: Alstonia scholaris (Family-Apocynaceae) is a common medicinal plant of India. The aqueous as well as partially purified extracts of stem bark and leaf of Alstonia scholaris has molluscicidal as well as in vivo and in vitro anti-cholinesterase (AChE) activity against the snail Lymnaea acuminata. The aqueous stem-bark extract shows strong molluscicidal activity in comparison to leaf at all exposure periods in time as well as dose dependent manner (LC50 value decreases from 665.82 mg L–1 (24 h) to 138.32 mg L–1 (96 h) and 940.45 mg L–1 (24 h) to 485.06 mg L–1 (96 h) for stem bark and leaf extracts, respectively). Same trend was observed in case of partially purified extracts. The anti-AChE activity of A. scholaris was also time as well as dose dependent. At LC90 (24 h) of aqueous and partially purified stem bark and leaf extracts of this plant parts did not cause any mortality among fish in a mix population of snails and fish, which support the view that plant product are safer in use as molluscicides for non-target organism.