The aim of the work was to study the influence of stimulant drugs – the regenerating biological stimulant (RBS) and Imunolac on the immunological state and productive qualities of piglets. RBS is a complex of organic compounds of animal tissue that stimulates nonspecific immunity and increases the protective functions of the body. Imunolac is a preparation of enzymatic hydrolysis of the cell wall of Lactobacillus, activating the cellular and humoral factors of non-specific animal resistance. To achieve this goal, the following tasks were set: to find out the microclimate condition and sanitary regime in the boxes in which the experimental animals were kept; – to study the influence of immunostimulating drugs on the growth and intensity of the test pigs, their safety; to study the dynamics of immunological parameters (circulating immune complex (CIC), T-and B-lymphocytes), the content of immunoglobulins (Jg G, Jg M and Jg A) while using RBS and Imunolac. The research was carried out in the pedigree plant «Stepnoy» of the Zaporozhye region on pigs of the Large white breed × Landras. Piglets of the control group were injected with 0.9% sodium chloride solution at a dose of 1 ml/head. During the experiment, the microclimate was monitored for temperature, relative humidity, air speed, carbon dioxide, ammonia, air contamination with microflora. Cellular indices were determined from the ratio of neutrophils to E. coli according to VG Gostivu, 1956, bactericidal activity of blood serum (BASK) – according to the method of O.V. Smirnova and TA. Kuzmenoy, 1966, lysozyme activity of blood serum (LASK) according to V. Dorofeychuk, 1968. The content of T lymphocytes was determined according to M. Jondal, 1973, B-lymphocytes – according to N.S. When piglets were grown at the temperature lower than 3,5–8 °C, humidity – by 5–8% higher, the parameters of NH3 and CO2 higher by 0.8–1.2%, the contamination microflora was twice as much as recommended by the sanitary norms the genetic productive potential of the animals is not fully realized, while – the highest daily average weight gain was in the pigs, which were injected intramuscularly with RBS growth stimulant. They exceeded the animals from the control group on the 20th and 30th days of the experiment – by 24.3% and 14.4%, live weight – by 15.3% (P < 0.05). The growth rate in the animals that were injected with imunolac was less expressed; the diseases with the symptoms of dyspepsia and bronchopneumonia were registered in 5–10% of the pigs from the experimental groups that received RBS and imunolac that is 10–12 times less as compared to the control group; in the pigs from the experimental group 1, the BASK was at the level of the average values of 56.52 ± 2.03%, from the experimental group 2 – 59.48 ± 1.80%, by 5.2% higher (P < 0.05); LASK indices in the animals of the experimental group tended to increase but the differences were not trustworthy (P < 0.5); the cell indices of resistance in the pigs that received RBS were higher: the phagocytic activity of blood serum – by 4.3% (P < 0.05), phagocytic number – by 9.7% (P <0.05); the highest concentration of immunoglobulin of class Jg G (21.82 ± 0.3 mg/ml) was revealed in the animals that received RBS preparations, the concentration of the above immunoglobulins was slightly below – 19.86 ± 0.18 mg/ml in the pigs that received imunolac (0–1). For immunoglobulins of class Jg M and Jg A, the fluctuations  between the experimental groups were within the limits of 2.23 ± 0.01 and 2.36 ± 0.09 mg/ml.