Abstract: A peptide with an amino acid composition such that the peptide is amphipathic, cationic and forms a stable &agr;-helix and has the following structure comprising at least 12 amino acids R1-R2-A1-B1-(A2-B2-C1-A3)m-(C2)n-R3, wherein A=an amino acid selected from the basic amino acids Lys,Arg or His B=an amino acid selected from the aromatic amino acids Phe, Trp or Tyr C=an amino acid selected from the group comprising the hydrophobic amino acids Leu, Ile, Val or Ala, and said peptide has either the orientation according to the formula or the retro orientation thereof, wherein at least 0-m of the repetitive sequence motifs (A2-B2-C1-A3) have the retro orientation and the remaining repetitive motifs (A2-B2-C1-A3) have the orientation as presented in the formula and wherein, R1-R2- and R3 are a number of amino acids, and wherein m=1-10, preferably 2-8, more preferably 2-5 and n=1-3, a pharmaceutical composition comprising such a peptide application thereof in treatment or