The 4'-EPI-doxorubicin (4'-EDX) has shown antitumoral activity against a broad spectrum of human tumors. The same clinical reports have shown therapeutic activity comparable to doxorubicin (adriamycin), but a lower cardiac toxicity. 4'-EDX cardiotoxicity appears after highest cumulative doses: 935 mg/m2 bs for 4'-EDX vs 550 mg/m2 bs for adriamycin. Moreover we have observed a protective action of the calcium antagonist gallopamil. We have found an improvement in ventricular performance after using gallopamil, and a reduction of 4'-EDX cardiotoxicity. Cardiac function was evaluated by EKS, STI, echography, myocardial scintigraphy course. Our result indicates the possibility of treating tumors without serious cardiotoxic by 4'-EDX and gallopamil.