The peptides of the killing activity of anti- micro-organism are an important part of the innate immune response of the organism. They are produced by plants and animals constitutively or in response to infection by microorganisms . This paper presents the current knowledge and views on the interaction of antimicrobial peptides from microbial cell structures and on the probable mechanisms of action of these compounds. Antimicrobial peptides may exert its effect by the suicide : formation of membrane pores ( hypothesis ? Forming drums) or ion channels , membrane disintegration model ? Dywanopodobny and induction of transient holes in the model ? Robakowatego bend membranes , as well as alternative mechanisms of action , which include interaction with DNA or interfering with the synthesis of proteins, such as membrane . Explains what is conditioned selectivity for peptides and describes their physiological role and clinical trial applications .