AbstractThe interaction of water‐soluble cationic polyelectrolytes based on vinylamine, aminoalkyl methacrylates and their quaternary ammonium salts with bacterial cells has been investigated. It was established that cationic polyelectrolytes exhibit antibacterial activity, change the membrane permeability, increase the transport of low‐molecular weight substances into the cell and suppress some bacterial enzymes. The level of activity is determined by the content of ionogenic groups in the polyelectrol