The polyethiology of the respiratory diseases and the lack of effective vaccines to prevent them (except for influenza) underline the need for clinical trials and the practical application of immunomodulatory preparations that could become part of the group of anti-viral drugs with a wide range of activity. It has been demonstrated that amixin and poludan, the drugs made in our country, cause an increase of the serum IFN level, enhance the ability of leukocytes and lymphocytes to produce IFN-alpha and IFN-gamma, and lead to the activation of NK and peripheral blood phagocytes. In other words, they have an immunostimulating activity. The number of CD3(+), CD4(+), CD8(+), CD19(+) cells, the level of the Ig A, IgG, IgM and several other parameters of the immune system were not affected by these drugs. It has been demonstrated that amixin and poludan show good drug tolerance, without side effects on the hemogram in individuals who were taking these drugs just for disease prevention. The studied immunomodulators have a significant prophylactic activity in the cases of the polyethiologic group of acute respiratory viral infection during the seasonal peak of the disease, with a coefficient of efficiency of 3.6 (amixin) and 2.1 (poludan), and corresponding protection indices of 72.1% and 52.7%. Having the same chance of getting infected, individuals protected with these drugs often have the disease in a milder or asymptomatic form.