Intestinal microflora in healthy rats and its changes under the conditions of experimental chronic toxic hepatitis were studied. The study revealed that in intact animals the microflora of the small intestine was represented by bacteria of the genera Escherichia, Enterobacter, Moraxella, Alcaligenes, Staphylococcus, Streptococcus. Bacteria of the genera Escherichia, Enterobacter, Moraxella, Alcaligenes, Staphylococcus, Corynebacterium and Clostridium were isolated from the large intestine. No bacteria were found in the systemic blood, the contents of the portal vein, as well as in the liver parenchyma and the mesenterial lymph nodes. As the result of dysbiosis induced by the introduction of kanamycin and in chronic hepatitis caused by carbon tetrachloride the sharp decrease in the species composition of microbial communities (up to 2-3 species) in the small intestine and was observed along with penetration of bacteria into the blood stream, the mesenterial lymph nodes and the liver parenchyma. The tendency towards the restoration of the quantitative and qualitative microflora composition was noted following administration into experimental animals of bactisubtil and amixin--an inductor of interferonogenesis.