pesticides are used as essential tools to control vector-borne diseases and agricultural pests and maintain quality and quantity crop production. Scientists attempt to use derived plant natural products due to environmental safety and low mammalian toxicity. Therefore, the cytotoxicity of malathion and Nepeta crispa essential oil against vertebrate L929 and invertebrate Sf9 cell lines were investigated. about 2× 10 3 cells were placed into the wells of a 96-well plate experiments. Then appropriate concentrations of malathion and N. crispa essential oil added to the wells. The cells were allowed to grow for 3-5 days and estimated the cell numbers. Control cell wells contained only cells with DMSO. All treatments and controls repeated at least four replicates. about 2× 10 3 cells were placed into the wells of a 96-well plate experiments. Then appropriate concentrations of malathion and N. crispa essential oil added to the wells. The cells were allowed to grow for 3-5 days and estimated the cell numbers. Control cell wells contained only cells with DMSO. All treatments and controls repeated at least four replicates. plant essential oil not only had no negative effects but also had boosting effects on the L929 cell viability. Nepeta crispa essential oil had negative effects on the Sf9 cell viability with the differences that derived plant natural products containing environmentally friendly and readily biodegradable derivatives, hydrolyzing rapidly in nature and nearly having no destructive effects on mammals and environment.