In the experiments in vitro using the primary mononuclear cells (MNC) culture of the human peripheral blood the influence of interferonogenic yeast RNA-tilorone molecular complex on the DNA, RNA and protein synthesis was studied. The complex was shown to inhibit the insertion of 3H-thymidine, 3H-uridine and 3H-leucine into DNA, RNA and protein of MNC total pool (by 13, 1 and 40% respectively); that was practically conformed with this synthesis inhibition upon to a natural origin polynucleotide interferon inducers--lariphan (9, 0 and 57% respectively) and ridostin (9, 0 and 56% respectively) action, and at the same time rather less than poly(I)-poly(C) (14, 5 and 62% respectively). In the case of preliminary cell stimulation by the mitogen PHA the complex revealed comitogenic action at a concentration 25 micrograms/ml, that corresponded to optimal for interferonogenesis; the increase of the doses till 100-1000 micrograms/ml lead to in the reversal effect. To proceed from mutual relation between interferonogen preparations influence on the mentioned synthesis and their cytotoxicity the conclusion was about made the complex promising usage as an interferon inducer both in vitro and in vivo conditions.