A St. Jude Medical Silzone was implanted in a 72-year-old female, suffering from mitral valve disease. Four months later, the patient had acute cardiac failure due to partial detachment of the prosthetic valve. The mitral annulus was ulcerated and there were multiple erosions in the myocardial tissue in contact with the prosthetic valve. Histological examination revealed chronic inflammation with hemosiderine deposits and giant cells. No allergy to silver ions was found. The silver-coated sewing cuff had caused a chronic inflammatory reaction due to a toxic reaction to silver. The Silzone valve was withdrawn from the market on January 2000.