Antibacterial peptides and their multimeric analogues, with a wide range of action and low haemolytic activity are described. In particular, the peptide molecules exhibit a high antimicrobial activity against numerous bacterial species, with reduced cytotoxicity and a low haemolysis rate. The molecules of the invention are advantageously usable as therapeutic agents and coadjutants against infections caused by strains that are resistant to common antibiotics.