Aim: Evaluation of the antitumor activity of the new drug Dekoglitz in animals with tumor strains of Sarcoma 45 in comparison with the drug dekocin, from which it was obtained, as well as with 5-fluorouracil and etoposide, and on ovarian tumors (OT) in comparison with the drug dekocin and identification of the effect of Dekoglitz on NA synthesis and internucleosomal DNA degradation. Methods: The study of preparations was carried out on 68 outbred rats with transplanted C-45 and OT tumors. The alkylating effect of the drugs was studied on cells tumor of Sarcoma 180. Results: The antitumor activity of dekoglitz on Sarcoma 45 was high, about 98/96%, with a remission rate of 80%. Its effect was 28-24% higher than that of dekocin. On OT, the effect of decoglitz with intraperitoneal administration reached 89/76% with a remission rate of 40%, with oral administration 96/86% with a remission rate of 60%. Conclusion: The study of the new drug Dekoglitz on animals with a tumor of Sarcoma 45 revealed its higher activity (by 20-27%) in comparison with the original Dekocin, 5-fluorouracil and etoposide with a lower level of side effects. On OT, the effect of Dekoglitz was 35-40% higher, especially after oral administration. Apparently, the great ability to suppress the synthesis of NA and carry out internucleosomal degradation and fragmentation of tumor DNA by the new drugs dekoglitz explains its antitumor efficacy, which is greater than that of Dekocin (K-18) in experiments on tumors.