AIM: Spider venom is a rich source of antibacterial peptides, whose hemolytic activity is often excessive.METHODOLOGY: How to get rid of it? Using latarcins from Lachesana tarabaevi and oxyopinin Oxt 4a from Oxyopes takobius spider venoms we performed coarse-grained molecular dynamics simulations of these peptides in the presence of lipid bilayers, mimicking erythrocyte membranes. This identified hemolytically active fragments within Oxt 4a and latarcins. Then, we synthesized five 20-residue peptides, containing different parts of the Oxt 4a and latarcin-1 sequence, carrying mutations within the identified regions.CONCLUSION: The antibacterial and hemolytic tests suggested that the three of the synthesized peptides demonstrated substantial decrease in hemolytic activity, retaining, or even exceeding antibacterial potential of the parent peptides.