Sternal or mediastinal infections after heart operation occurs infrequently but carries a high cost in money, morbidity, and mortality. At our hospital, Staphylococcus species cause most of these infections and is uniformly sensitive to vancomycin. However, the relative low concentration of vancomycin in sternal bone was noted given intravenously. Topical vancomycin was therefore considered to apply on the cut edege of sternal bone before closure in patients receiving coronary artery bypass graft to evaluate the effect on reducing the infection rate of staphylococcus related mediastinitis (6). In addition, we try to observe that prophylactic use of topical vancomycin will increase the risk for acquiring resistant pathogen such as VISA (vancomycin-intermediate S. aureus), VRSA (Vancomycin-resistant S. aureus), VRE (vancomycin-resistant enterococcus)