Mitral valve prolapse syndrome (MVPS) is the name given to the heart valve abnormality described by Barlow over two decades ago. This condition is of particular importance to the dentist as these patients are thought to be at risk of developing infective endocarditis with routine dental procedures which may cause gingival bleeding. This paper is an updated version of an article that originally appeared in the University of Toronto Dental Journal in 1990. In 1984, guidelines for antibiotic prophylaxis were provided by the American Heart Association (AHA). More current prophylactic regimens are also presented, with emphasis on the current recommendations of the AHA, recently published in December of 1990.