This study was interested in evaluating the toxicity of an insecticide based on lambda-cyhalothrin, newly approved and widely used in agriculture in Algeria, on an alternativebiological model, the snail Helix aspersa.In order to achieve these objectives, we based our-selves on the evaluation of the degree of oxidative stress by monitoring the average weightof the snails, the level of total proteins and Glutathione-SH (GSH), as well as the enzymaticactivities of Glutathione S-transferase (GST ) and Catalase activity (CAT ) at the level ofthe hepatopancreas. We performed a histopathological examination of the kidney and hep-atopancreas.The results show that lambda-cyhalothrin causes a dose-dependent decreasein the average weight of snails, an increase in the content of total proteins, and a decrease inthe level of GSH , in parallel with the induction of GST activities and CAT. Histopathologicalexamination conirmed the toxicity of lambda-cyhalothrin in Helix aspersa.