Bacteremia that occurs after dental extraction is common. This study assessed the effect of topical antisepsis on the incidence and magnitude of post-extraction bacteremia. On hundred patients scheduled for elective tooth extraction were randomized among four groups: contr-l, mouthrinsing with sodium-p-toluene sulfonchloramide (chloramine-T), toothbrushing with chloramine-T, and irrigation with Lugol's solution. The results showed that 84% of the control group and 59% of the treatment groups had positive blood cultures (290 organisms isolated) after dental extraction. The duration and magnitude of these bacteremias were diminutive as documented by the six serial blood cultures taken for each patient, colony counts per milliliter of blood, and nitroblue tetrazolium and Limulus assays. Brushing the teeth or rinsing the mouth with chloramine-T before dental extraction significantly reduced the incidence of bacteremia (P less than .025) and the number of different organisms recovered from each patient (P less than .05). Thus, topical treatment with chloramine-T is a simple and effective means of reducing the incidence of postextraction bacteremia.