This therapy is considered to be the method of the future and, importantly, may become the only way to treat diseases caused by antibiotic-resistant bacteria. Bacteriophages do not attack eukaryotic cells. Their mechanism of action is to replicate (multiply) in the body and then destroy bacterial cells (which are harmful to our health). A specific type of phage attacks only a few, selected bacterial strains of one species. Unfortunately, the body has the ability to produce defence mechanisms against phages, forcing scientists to search for new types. Studies conducted so far show that the phage method is completely safe for the patient.