Eighteen pediatric patients with infective endocarditis (IE) were reviewed for "failure" of chemoprophylaxis; none had had a previous dental procedure. Surprisingly, published reports reveal a similarly low prevalence of dental extractions preceding IE, only 3.6% for 1,322 cases. Although bacteremia was associated with 40% of 2,403 reported extractions, it also was found in 38% of patients after mastication, and in 11% of patients with oral sepsis and no intervention. In a hypothetical month, ending with a single dental extraction, the cumulative exposure to these "physiologic" sources of bacteremia is nearly 1,000 times greater than it is from extraction. The current American Heart Association recommendations for intramuscular or intravenous chemoprophylaxis are impractical, and the discomfort and inconvenience may impede good dental care. The Committee also implies that gingival bleeding allows bacterial access to the blood stream, whereas experimental studies establish the lymphatics as the only access. Although oral chemoprophylaxis for major dental procedures appears prudent, the British regimen of a single dose of amoxicillin administered orally is much simpler and probably more effective. However, scrupulous oral and dental hygiene is undoubtedly superior in preventing IE than any chemoprophylaxis regimen.