Infective endocarditis is a serious complication in patients with underlying cardiovascular defects. The causative organisms are frequently part of the oral flora. There is a risk of development of endocarditis following transient bacteremia caused by oral microorganisms in association with dental procedures as well as in association with certain activities of daily living. Host susceptibility, including the presence of underlying cardiovascular defects, which are at increased risk of: becoming infected, is an important factor in calculating risks of bacteremia and resulting endocarditis. Chemoprophylaxis to prevent such infections may be justified in certain cases, and the American Heart Association has continued to develop guidelines for prevention of endocarditis in patients undergoing dental procedures.