Clostridium difficile pathogen is a cause of the most frequent nosocomial infection, which is antibiotic-associated diarrhea. Antibiotic treatment causes disruption of the microbiome balance, which makes the gut a friendly environment for the pathogen. It leads to pseudomembranous colitis, toxic megacolon and even death. Clostridium difficile infection (CDI) is particularly dangerous to elderly patients, leading to the highest mortality rate. C. difficile is equipped with many virulence factors such as toxin A and B, binary toxin CDT, flagellum, S-layer proteins, Cwp66 and GroEL proteins, protease Cwp84, fibronectin-binding protein and the ability to form biofilm and spores. Problems with anti-CDI therapy prompt researchers and clinicians to seek alternative ways of therapy. Identification of immunological epitopes in outer layer proteins and the use of them as antigens for anti-CDI vaccines would be a rational approach to prevent the disease, but unfortunately such vaccines are not available yet. In this article we review the course of the disease, virulence and risk factors. We summarize briefly epidemiological data and the latest achievements in CDI treatment.