The subject the present invention is a method of producing a pharmacologically stable form of purified and lyophilised bacteriophage preparations of increased stability and antibacterial activity, characterized in that phages produced from a bacterial lysate, for example by ultrafiltration on ultrafiltration membranes, containing a high molecular weight preparation of purified phages is stabilised most preferably with a probiotic extract in the presence or absence of neutral salts and/or organic solvents, lyophilised, characterised via HPLC chromatography, by SDS-PAGE, and bacterial lysis biological assays, and then stored under a vacuum, where the active lyophilisate is destined for phage therapy of infections and tumors.