: The use of antibiotic prophylaxis to prevent distant site infections (DSI) from oral pathogens remains a controversial issue in clinical practice. Little is known about the incidence, nature, magnitude, and duration (INMD) of bacteremia from naturally occurring or invasive dental procedures, or the impact of prophylactic antibiotics on the INMD. The major purposes of this prospective, randomized, clinical study of 300 subjects is to: 1) determine and compare the true INMD of bacteremia resulting from a highly invasive dental office procedure (single tooth extraction) and a minimally invasive and naturally occurring source of bacteremia (tooth brushing), from 10 specific oral pathogens (S. mitis, S. sanguis. S. Oralis. S. intermedius, S. mutans, S. Salivarius. F. nucleatum, A. Actinomycetemcomitans, E. corrodens and P. gingivalis) that have been reported to cause DSI; and 2) measure the effect of the American Heart Association's guidelines for amoxicillin prophylaxis on the INMD of bacteremia resulting from a single tooth extraction. Subjects will be randomized into three equal into three equal groups: extraction with amoxicillin, extraction with placebo, and tooth brushing. Blood for aerobic and anaerobic bacterial cultures and PCR will be drawn at six time points before, during, and following these oral procedures. INMD will be determined as follows: 1) incidence figures for each blood draw will employ a highly sensitive, broth-based blood culturing system (BACTEC); 2) nature will be determined by conventional methods of speciating pathogens cultivated by BACTEC, and we will improve the specificity of the oral pathogens from BACTEC with the use of gene sequence analysis; 3) magnitude of bacteremia will be determined by PCR for each blood sample; and 4) bacteremia duration will correspond to the presence of oral pathogens in sequential blood draws following tooth brushing and extractions. This study will provide a more complete understanding of the impact of invasiveness (i.e., brushing vs. extraction) and the degree of oral disease on the INMD. Additionally, we will have unique and critical data for the development of both future research and evidence-based guidelines concerning antibiotic prophylaxis for individuals currently felt to be at risk for DSI.