Multicellular organisms exist in constant interaction with various species of microflora both at the body surface and in internal media. The mechanism of recognition of conservative molecular structures of infectious origin formed at the earliest stages of evolution before the appearance of the genes of the immunoglobulin superfamily in jawed vertebrates (Gnathostomata) that made up a basis for the development of clonal specificity of B- and T-lymphocytes as adaptive immunity factors. This paper considers the mechanism of action of cycloferon as an inductor of endogenous interferon synthesis and the new prospects for its application in clinical medicine.