Cardiological adverse events after oncological treatment are related to given drugs and patients. Cardiotoxicity is more often observed in the female population. The reason for this phenomenon is unknown. There are no differences in mechanism and duration of cardiotoxicity between men and women. Temporary dysrhythmia, heart failure and cardiomyopathy are the most often adverse effects after oncological treatment. Pathomechanism of cardiomyopathy is related to the presence of free radicals. Prevention against cardiological adverse effects is very important because of the limited options to reverse them. Prevention includes not exceeding the cumulative dose, the anthracycline dose fractionation, adequate qualification for cardiotoxic treatment, liposomal doxorubicins use or dextrasoxane administration to restrict free radicals.