Patients with certain cardiovascular abnormalities are recognised to be at risk-and some at high risk-of developing infective endocarditis following episodes of bacteraemia. Whenever a clinically important bacteraemia is anticipated in such susceptible patients, chemoprophylaxis (use of systemic antimicrobials) is advocated. However, the effectiveness of such measures remains unclear. Patients undergoing dentistry/ oral surgery (especially extractions) experience bacteraemias (mainly viridans streptococci) lasting minutes. For susceptible patients undergoing the latter procedures, it is appropriate to sensibly educate them about the risks, ensure good dental hygiene, consider prior topical antisepsis, and he vigilant to the possible failure of chemoprophylaxis. Currently advocated chemoprophylactic guidelines are confusing and ambiguous. For patients susceptible to infective endocarditis--including those at high risk--undergoing potentially bacteraemic dental/oral surgical procedures, the recommendations in this account have been simplified. In individuals with a history of penicillin hypersensitivity or recent exposure, instead of erythromycin, the use of clindamycin (orally) or vancomycin (parenterally) is stressed.