Abstract: Extensive and indiscriminate use of synthetic compounds and natural compounds obtained from plant sources have resulted into serious threats to not only the aquatic ecosystem but also to human health. Aqueous seed extract of the plant Croton tiglium L. is used in many traditional medicines to treat various ailments in many developing countries. The extract is also used for killing fishes for consumption in Manipur, India. However, the side effects and safety measures are not well studied and evaluated. The present study aims to investigate major phytochemical constituents, acute toxicity and genotoxicity of the aqueous extract. The phytochemical screening was carried out using chemical methods; acute toxicity test was performed using zebrafish as a model organism and genotoxicity potential was evaluated by in vitro plasmid DNA fragmentation analysis. Our results show that the exposure of aqueous extracts of Croton tiglium cause increase plasmid DNA strand breakage in a dose dependent manner. The aqueous extract of Croton tiglium also showed pisicidal activity. So, the plant extract need to be evaluated for its long term human health hazards and safety thoroughly before it could be used for therapeutic medicinal interventions.