Interferon-alpha is a biological response modifier with antiviral and tumoral effect that is used in the treatment of chronic viral hepatitis. Cardiovascular complications occurred in clinical trials of interferon. The most common presentations of cardio toxicity were cardiac arrhythmia, dilated cardiomyopathy, atrial extrasystole and symptoms of ischemic heart disease, including myocardial infarction and other effects less common and dangerous: low-level conduction impairment or reversible hypertension. The physiopathology of this cardiotoxicity remains unknown, but rigorous cardiological monitoring of all patients receiving this treatment seems necessary.