Mice treated with lethal doses of adriamycin (A1) (IP) are rescued with a single IP dose of 3,5,5-trimethyl-2-morpholinon-3-yl radical dimer (TM3). The in vivo rescue is assumed to be analogous to the in vitro reaction of TM3 with A1 that produces the non-toxic 7-deoxy-adriamycinone (7dAone). TM3 prevents death if given within 60 min following A1 administration. Control A1-treated mice died by 8 days (median survival time) whereas TM3 rescued A1-treated mice had a median survival time of greater than 60 days.