IT IS NOW five years since patients with subacute bacterial endocarditis were first successfully treated with penicillin. From the first it was apparent that good immediate results could be expected in a great majority. Enough time has now elapsed to permit a preliminary appraisal of the end results of penicillin treatment. Recent studies have shown increasing interest in this aspect of the disease. Many observers, particularly Fiese1and, later, Rapoport and Ellis,2have commented on the appearance of cardiac insufficiency. This complication, rather than inadequate antibiotic therapy, has generally been recognized as the most frequent source of failure. Other studies, however, emphasize embolic phenomena, aneurysms and renal failure as well. Christie,3in his study of 269 patients treated with penicillin, listed 73 deaths due to either heart failure alone or heart failure in combination with other causes. There were 8 deaths from uremia, 15 from embolic effects,