Recently, a new class of surfactants that combines two contradictory functions has appeared. They can be used as effective antioxidants protecting model and biological objects against peroxidation and its negative consequences, thanks to the antioxidant functional group incorporated into the hydrophilic part of the molecule. On the other hand, they may be applied as common pesticides thanks to their intensive interaction with biological membranes that leads to destruction and death of the unwanted microorganisms. Both applications depend on the concentration of the bifunctional surfactants (BS) used. The work contains results of the studies on a possible pesticide application of the bifunctional surfactants. Planar lipid membranes (BLM) were used as model membranes.