Hall et al78 reported that neither penicillin V nor amoxicillin therapy was effective in reducing the frequency of bacteremia compared with untreated control subjects. In patients who underwent a dental extraction, penicillin or ampicillin therapy compared with placebo diminished the percentage of viridans group streptococci and anaerobes in culture, but there was no significant difference in the percent- age of patients with positive cultures 10 minutes after tooth extraction.24,66 In a separate study, Hall et al77 reported that cefaclor-treated patients did not have a reduction of postpro- cedure bacteremia compared with untreated control subjects. Contradictory published results from 2 studies showed reduc- tion of postprocedure bacteremia by erythromycin in one75 but lack of efficacy for erythromycin or clindamycin in another.78 Finally, results are contradictory with regard to the efficacy of the use of topical antiseptics in reducing the frequency of bacteremia associated with dental procedures, but the preponderance of evidence suggests that there is no clear benefit. One study reported that chlorhexidine and povidone iodine mouth rinse were effective,79 whereas others showed no statistically significant benefit.52,80 Topical anti- septic rinses do not penetrate beyond 3 mm into the periodon- tal pocket and therefore do not reach areas of ulcerated tissue where bacteria most often gain entrance to the circulation. On the basis of these data, it is unlikely that topical antiseptics are effective to significantly reduce the frequency, magnitude, and duration of bacteremia associated with a dental procedure. 