The aim of this work was to to determine the integral leukocyte indices in animals with toxic damage by acetaminophen on the background of protein deficiency. The study was conducted on 4 groups of animals: Group I - control animals (K); II – rats kept on a low-protein diet (LPD); ІІІ – animals with acetaminophen-induced liver injury receiving complete ration (AII); IV – animals with acetaminophen-induced liver injury that were previously maintained on semi-synthetic low-protein ration (LPD/AII). Preparation of blood smears, their fixation and staining was carried out by the generally accepted method. The ratio of different types of leukocytes in stained blood smears was calculated using a standard method using a leukocyte counter and a microscope (eyepiece × 10, objective × 100). Standard formulas were used to calculate integral hematological indices. It was established that the supply of protein in the diet is critical for the functioning of the immune system under conditions of acetaminophen intoxication, since under these conditions there is a change in leukocyte indices, in particular, the index of immunoreactivity, the index of leukocyte shift, the index of the ratio of neutrophils and lymphocytes, the index of the reactive response of neutrophils, which indicates the intensification of inflammatory processes in the body and the formation of defects in the cellular link of immunity, disruption of the mechanisms of the specific immune response and the formation of a state of endotoxicosis. The obtained results can be used to develop approaches to the early diagnosis of impaired immunoreactivity in animals with toxic damage by acetaminophen against the background of dietary protein deficiency, while the studied integral hematological indicators can be used as additional early diagnostic markers of impaired immunoreactivity and endotoxicosis. Key words: acetaminophen, dietary protein deficiency, leukocytes, immunoreactivity indices