OBJECTIVE: Aim: To determine the main clinical and laboratory features and severity of colon dysbiosis in irritable bowel syndrome (IBS) and IBD in patients with NAFLD. PATIENTS AND METHODS: Materials and Methods: 80 patients with NAFLD were examined. Patients were divided into two groups. Group 1 (n=40) included patients with NAFLD in combination with ulcerative colitis (UC), and group 2 (n=40) included patients with NAFLD and IBS (clinically manifested by diarrhoea). At patients diagnosed the level of faecal calprotectin (FC) and a1-antirpsin (a1-AT). Changes in the quantitative and qualitative composition of the colon microflora were assessed. RESULTS: Results: In both groups of examined patients, a decrease of Bifidobacteria and Lactobacilli, as well as Enterococcus and E. coli with normal enzymatic properties was found compared with the control group. In patients with NAFLD and IBD, an increase in the level of FC was found in 23.8 times compared with the control group. As expected, there was an increase in the level of a1-AT in the blood serum, faeces and its clearance in patients of group 1. CONCLUSION: Conclusions: In patients with NAFLD, both UC and capital I, UkrainianBS have similar clinical symptoms. An effective biomarker for differentiating and choosing treatment tactics in patients with NAFLD and UC is the determination of the level of FC.