Antibiotic prophylaxis of endocarditis is very complex and does not allow simple wholesale recommendations. It is impossible to make recommendations for every eventuality. Antibiotic prophylaxis is indicated in patients at risk whenever surgery or procedures are performed on infected, colonized or contaminated tissues. The choice of antibiotic(s) and duration of use may have to vary depending on the individual patient or circumstances. Endocarditis may develop even after prophylactic antibiotics have been given. Patients should be warned of this possibility and instructed to seek medical advice in the event of any unexplained illness. Pediatricians and dentists should maintain a high index of suspicion regarding any unusual clinical event following a dental or surgical procedure.