There is a close relationship between intestine and liver, so-called ‘gut liver’ axis, especially in patients suffered from chronic liver diseases with significant degree of fibrosis. Small intestinal bacterial overgrowth and disturbance in the microbiota composition lead to an increase in the permeability of the intestinal epithelium, the development of endotoxinemia, the activation of pro-inflammatory cytokines and, as a consequence, an additional damage to hepatocytes.Objective. To estimate the incidence of bacterial overgrowth syndrome (BOS) in the small intestine in adolescents with chronic hepatitis C (CHC), to identify the interaction between this syndrome and cytolytic activity, the degree of fibrosis.Materials and methods. There is a group of 33 patients aged 12—17 years old with CHC. All children underwent a hydrogen breath test with lactulose. The degree of fibrosis was assessed by the results of liver elastography (Fibroscan), cytolytic activity was determined by the level of alanine transaminase in serum.Results. The frequency of BOS was 81.8% in the study group. As a result of the correlation analysis, no relationship was found between the development of BOS and the degree of cytolytic activity of chronic hepatitis C (criterion χ2= 0.914, p > 0.05). Also, there was no correlation between excessive bacterial contamination and the degree of fibrosis in the liver tissue (criterion χ2= 0.914,p> 0.05).Conclusion. BOS in children with CHC occurs much more often than in adults. However, no relationship was found between this syndrome and the severity of cytolytic activity, the degree of fibrotic changes in the liver.