Violations caused by various metabolic changes in the erythrocyte membrane lead to the formation of their pathological forms. As a result, anemia comes to the fore, due to the effect of toxic substances on the blood. Toxins are fixed on the erythrocyte membrane, which leads to its deformation, a decrease in the functional activity of red blood cells and an aggravation of the pathological process in the body, which erases the specificity of the clinical signs and makes the diagnosis and treatment of the disease difficult. Materials and methods. For the study, dogs aged 3-10 years with liver damage were selected, which were then divided into 3 groups. The first group and the second group underwent treatment, which included isotonic sodium chloride solution, Ringer-Lock solution, reopoliglyukin, 40% glucose solution, heptral, amoxoyl retard, vitamins B1, B6, B12, ascorbic acid, catazal, and lactulose stad. In addition to similar treatment, the third group used fresh frozen plasma. Venous blood was taken at the initial visit, then on the 3rd, 7th and 10th day of the study, a complete blood count was performed. The results of the study. When conducting a complete blood count in dogs with liver damage on the day of the first visit, the presence of moderate anemia was established. There was a decrease in the number of red blood cells, the level of hemoglobin and hematocrit. In the 3rd group, the best therapeutic effect was observed already on the 7th day of treatment. As a result of studies in sick dogs, macrocytic anemia was detected. In addition, an assessment of the morphology of red blood cells showed the presence of altered forms of red blood cells. So, echinocytes were detected, the number of which in dogs on the day of admission was almost 2 times higher than the norm, a large number of stomatocytes, which was 3.8 times higher than the reference values. In addition, in all sick animals, acanthocytes and codocytes were observed in the blood. Conclusion. As a result of the studies, normochromic macrocytic anemia was found, as well as moderate anisocytosis of red blood cells with the appearance in the blood of pathologically altered forms of red blood cells that occur in liver pathologies. When evaluating various treatment regimens, the greatest effectiveness is observed in the 3rd group, where by the 10th day all indicators of erythrocyte morphology are normalized, in contrast to the 1st and 2nd groups, where pathological forms of red blood cells are found in large quantities in blood smears. These changes, apparently, occur as a result of the rapid removal of intoxication due to water and the plasma content of additional components necessary for the body with liver damage. © 2020, Institute of Advanced Scientific Research, Inc.. All rights reserved.