FIELD : medicine.SUBSTANCE : invention relates to the field of medicine and is intended to inhibit and / or prevent the growth of microbio films. Antimicrobial agent contains lactoferrin, pharmaceutically acceptable additives and mono[(2-dimethylamino)ethyl]carboxylic esters of the general formula R-O-(Et)-N(Me)2, where R is a carboxylic acid selected from the range : fumaric, succinic, maleic, α-ketoglutar, oxalic, D, L-malic, pyruvic, Et - ethyl and Me - methyl. Ratio (wt.) Lactoferrin / esters of carboxylic acids is from 1/1 to 1/3.EFFECT : use of the invention allows to increase the antiseptic properties against the vast majority of gram-positive and gram-negative bacteria, fungicidal properties against fungi, and also provides effective prevention and treatment of conditions of the mucous membranes and dental diseases.1 cl, 16 tbl, 8 dwg