Preliminary data are reported that support the suspicion that organic peroxides may possess carcinogenic properties. This suspicion in large measure relates to the acknowledged mutagenicity of certain peroxides. As a possible mechanism of action it is suggested that peroxides may act by catalyzing the depolymerization of deoxyribonucleic (DNA) and ribonucleic acid (RNA). This radiomimetic property may provide a fundamental bridge between the carcinogenicity of ionizing radiation and that of organic peroxides when used in pure form. Emphasis has also been directed to the carcinogenic properties of epoxides. Organic peroxides may lead to the formation of epoxides, and the established carcinogenicity of epoxides has resulted in the accumulation of a large body of information relating to the mechanism of their action. Of particular significance in this area is their capability of acting as crosslinking agents. The possibility of utilizing the established carcinolytic properties of certain carcinogenic agents in the study of the carcinogenic properties of organic poroxides is discussed. (auth)