We report the case of a 52-year-old woman with recent diagnosis of acute myocarditis and pericarditis, admitted for fever, tachycardia, and dyspnea upon exertion. Hematochemical parameters and instrumental examinations suggested iatrogenic hyperthyroidism and secondary dilated cardiomyopathy. Although gathering information about the medication used at home was initially difficult because of the patient’s refusal to cooperate, she ended up by disclosing the regular assumption of an iodocasein drug. A complete and stable regression of the clinical picture was reached by suspending the iodine derivative and using cardiovascular drugs