The article presents modern ideas about Clostridium difficile (C. difficile) infections: the modern classification is given, the questions of epidemiology, etiology, the pathogenesis of intestinal disorders, the clinical aspects of this disease, as well as laboratory, endoscopic, morphological manifestations are considered. Mo­dern international approaches to the treatment of C. difficile infection are presented. C. difficile-associated colitis is a disease that develops with an intestinal microbiome disorder with excessive colonization of C. difficile, the toxins of which cause inflammation and damage to the colon mucosa and diarrhea. The antibiotics intake leads to the inhibition of endogenous microflora and propagation of C. difficile due to spore-forming plasmids; after drug withdrawal spores go into the vegetative form of bacteria and begin to produce toxins; as a result of damage to the endothelium, extensive inflammatory changes in the mucous membrane of the colon, patches of necrosis are formed on the surface of the epithelium with the formation of pseudomembranes (exudative plaques). The Clostridial infection leads to a wide range of clinical manifestations from an asympto­matic course, moderate, uncomplicated diarrhea to life-threatening pseudomembranous colitis — a severe clinical form of C. difficile-associated colitis caused by the toxigenic form of C. difficile, a cha­racteristic feature of which are fibrinous deposits on the colon mucosa (pseudomembranes) identified by endoscopic exa­mination. The gold standard and the most informative method for verifying a diagnosis is the detection of C. difficile toxins in feces. In the diagnosis of C. difficile-associated colitis, an important role belongs to the assessment of laboratory parameters, endoscopic and morphological examinations. When pseudomembranous colitis is diagnosed, treatment should be started immediately. The first step is to cancel the antibiotic that has caused diarrhea. The necessary part of standard therapy for patients with C. difficile-associated colitis is an antibiotic therapy, which limits C. difficile colonization of the intestines and has an anti-inflammatory effect. C. difficile is most sensitive to vancomycin and metronidazole. The enteral administration of antibiotics is necessary since their parenteral administration in the intestine does not always create a sufficient concentration of antibiotics, and therefore, complete liquidation of C. difficile may not occur. The article shows and analyzes the clinical case of the patient with this disease who was treated at the Institute of Gastroenterology of the National Academy of Medical Sciences of Ukraine.