A 44-year-old white female with chronic rheumatic heart disease and mitral insufficiency was admitted to the hospital for cardiac catheterization and mitral valve replacement. On the ninth postoperative day the patient experienced a sudden onset of chest pain, hypotension, and died shortly therafter. Autopsy revealed multiple mural thrombi of the left atrium, one of which occluded the mitral orifice. Histologic examination showed a granulomatous and non-specific interstitial myocarditis involving all chambers of the heart. In the granulomas, both inside and outside giant cells, rounded foreign bodies were noted which stained light blue with hematoxylin and eosin, red with the periodic acid Schiff reagent, dark bluish-black with Gram's iodine, and showed Maltese cross birefringence under polarized light. These particles were identical with starch granules from surgical glove powder. The cause of death was acute mitral occlusion form a flapping mural thrombus.