In experiments on rats (290 animals) exposed to chronic gamma-radiation with the total dose of 10.0 Gy it was detected that prescription of synthetic pharmaceutical of the dihydropyridine class--glutapyrone--together with drinking water during 6 months reduced the rate of malignant neoplasms from 26.5% in the control group to 13% in the treated animals. In radiation-exposed rats that received glutapyrone there was a narrowing of spectrum of the emerged neoplasms (connectively-tissual tumors only) as compared to the animals of the radiated control group, where blastomas of epithelium and lymphoid origin were also revealed. Low toxicity of glutapyrone and its anticarcinogenic action show the potential for this preparation to be used in practice.