The immune system of humans and higher animals performs an important function of maintaining the constancy of the internal environment of the body by detecting and eliminating foreign substances of an antigenic nature, both endogenously created and exogenously penetrating. This function of the immune system is performed by factors of innate and acquired immunity. As the name suggests, immunostimulants are the agents boosting the immune response. The new chemical series of compounds is promising for the search new effective immunostimulating drugs. Acute toxicity and the effect on peripheral blood hemogram parameters and on the subpopulation composition of lymphocytes were determined in the compounds (piperidine-containing derivatives):ethoxyethyl)-4-ethynyl-4hydroxypiperidine) dihydrochloride and, 1:1 complexes of β-cyclodextrin with 1-(2-ethoxyethyl)-4-(2-ethoxyethoxyl)-4-ethynylpiperidine, 1-(2-ethoxyethyl)-4-(2-methoxyethoxyl)-4-ethynylpiperidine, 7-(2-methoxyethyl)-2,2-dimethyl-3-thia-7-azabicyclo[3.3.1]nonane or 3-(2-morpholinoethyl)-7-(3isopropoxypropyl) diazabicyclo[3.3.1] nonane with β-cyclodextrin. Compound ˗ 1-(3-n-butoxypropyl) piperidine-3-methyl-4-spiro-5'-imidazolidine-2',4'-dione, exceeds the immunostimulating activity of the comparison drug of levamizole by 3.1 times and shows low toxicity.