Studying influence of derivatives 3-oksipiridin, drugs «mexidol» and «mexicor» made to laboratories cardiofarmacology scientific research institute Ecological medicine KSMU, on indexes of collateral coronary blood flow and endothelial dysfunction in experiments on rats and dogs. The received results have allowed to position the expressed correction of endothelial dysfunction at application of drugs «mexidol» and «mexicor» in a dose of 30 mg/kg. Analysis of a collateral coronary blood flow at narcotized dogs has shown identical orientation their actions of antioxidants «mexidol» and «mexicor». At the same time, mexicor on the favorable dynamics of the majority of indexes surpassed mexidol.