An antitumor agent with estrogenic activity, penetrating into tumor tissues, decomposes under the action of acid phosphatase to form diethylstilbestrol. It binds strongly to cytoplasmic sex hormone receptors, inhibits the incorporation of thymidine into nucleotides, inhibits aerobic glycolysis, mitosis, growth and migration of tumor cells, androgen synthesis, and has a cytostatic effect in androgen-dependent neoplastic diseases.