Viral infections provoke dysbalance in the interferon system and inhibition of the cellular and phagocytic responses of the host. Long-term persistence of pathogenic viruses and bacteria induce atopy and could aggravate chronic respiratory diseases. The up-to-date classification of immunomodulators is described. High efficacy of interferon inductors, such as cycloferon and some others as auxiliary means in therapy or prophylaxis (immunorehabilitation) of viral respiratory infections in adults and children was shown.