Long experience in the use of various iodine preparations has shown that while possessing pronounced antibacterial and antiviral properties, wide-spectrum antimicrobial activity, and lacking mutagenic and teratogenic effects, they are toxic when introduced to the human body, which significantly narrows the scope of their clinical application. The search for alternative ways to solve the problem of high toxicity of inorganic iodine compounds has led to the development of iodine-containing organic complexes. The manifestation of the phagocytic response is a significant indicator of the body reactivity state and level of its immune activity. The coordination compound of iodine with alpha-dextrin and polypeptides was synthesized at the Scientific Center for Anti-Infectious Drugs JSC, the effect of which on the phagocytic activity of granulocytes and monocytes in BALB/c and C57BL/6 mice was studied. Phagocytosis is considered as one of the major host defense function, which is a fundamental component of the innate immune response /1/. Materials and methods: The animals of each line were divided into 3 groups of 10 mice, including 5 females and 5 males. Two doses of the drug were used in the study: 1/20 of maximum tolerated dose (MTD) is 125 mg/kg and 250 mg/kg (1/10 MTD) of animal weight. Blood was collected on day 14 after the administration of the drug. The analysis was performed by flow cytometry. Findings: It was shown that a new complex of iodine with bioorganic molecules upon repeated oral administration for 14 days in the examined doses did not affect the phagocytosis in BALB/c mice. The findings indicated that a new complex of iodine with bioorganic molecules at a dose of 250 mg/kg increased the phagocytic activity of both granulocytes and monocytes in C57BL/6 mice. Conclusion & Significance: One of the explanations for the differential effect of a new complex of iodine with bioorganic molecules on different lines of mice may be based on the genetic characteristics of these animals. Macrophages of BALB/c mice are known to be of M-2 type, which inhibits inducible NO synthesis and stimulates cell division. Macrophages of C57BL/6 mice are of M-1 type, which produces NO and inhibit cell division, and increases the cytostatic or cytotoxic activity of phagocytes. /2 - 4/. We can therefore conclude that a new complex of iodine with bioorganic molecules enhances the cellular factors of the natural resistance in the prototype mouse strains Th1 (C57BL/6), but not Th2 (BALB/c). This, in turn, fits into the single mechanism of action of the studied complex, namely, the activation of phagocytic cells through the induction of IFN-γ production and the ability of the complex to switch T cells to the Th1-type response path.