Respiratory pathology in calves, in particular acute non-specific bronchopneumonia, is extremely common, ranks second after gastrointestinal diseases and leads to significant economic losses. The effectiveness of antimicrobial agents of various pharmacological groups (tetracyclines, aminoglycosides, penicillins) has recently significantly decreased, which is associated with the formation of antibiotic-resistant strains of conditionally pathogenic bacteria. The problem of antibiotic resistance microorganisms that induce the development of an inflammatory process in the respiratory tract of calves forces the search for new therapi es, increasing the effectiveness of standard antibiotic therapy with the help of additional prescribing of various medicinal substances. The aim of the study was to study the effectiveness of the phytosorbent Hypericum Perforatum L. in the complex therapy of calves with acute non-specific bronchopneumonia. The therapeutic effect of Hypericum Perforatum L. phytosorbent was tested in the complex therapy of 97 calves with acute non-specific bronchopneumonia was studied. Calves aged 1.8±0.3 months and weighing 53.5±1.4 kg were selected for the experiment. For comparative study of therapeutic schemes, experimental animals were divided into two groups using the principle of paired analogues. Calves with bronchopneumonia-group I (n=42) were treated with the drug Florox at a dose of 1 ml per 15 kg of body weight, which corresponded to 20 mg/kg of Florfenicol, intramuscularly, twice with an interval of 48 hours. Calves with acute non-specific bronchopneumonia-group II (n=55) were also treated with the drug Florox at a dose of 1 ml per 15 kg of body weight intramuscularly, twice at 48-hour intervals with an additional prescription of phytosorbent Hypericum Perforatum L. at a dose of 5.0 g orally 1 time per day for 7 days. The effectiveness of therapy was evaluated by clinical and laboratory blood parameters. It was found that combined therapy of calves with acute non-specific bronchopneumonia with the use of Florfenicol and Hypericum Perforatum L. phytosorbent leads to a complete recovery 16.1 % more often than in animals treated with Florfenicol in a single mode. Combination of Florfenicol with Hypericum Perforatum L. statistically significant decreasing phenomena leukocytosis, increased phagocytic activity of neutrophils, reduced serum concentrations of C-reactive protein, α-globulin, β-globulin, the increase in the concentration of albumin, γ-globulin and IgG in the treatment of sick calves. In the blood of sick animals treated with a combination of Florfenicol with Hypericum Perforatum L. phytosorbent, compared with calves treated with Florfenicol in a single mode, the number of leukocytes in the peripheral blood significantly decreased and the phagocytic activity of neutrophilic leukocytes increased. These changes indicate a significant anti-inflammatory and immunomodulatory effect of Hypericum Perforatum L. in acute non-specific bronchopneumonia in calves. © 2020, Advanced Scientific Research. All rights reserved.