Twenty toothbrushes used by healthy subjects were screened for the presence of microorganisms. Microbes were dislodged from the brushes by vortexing, and an average of 4 x 10(3) CFU/mL were recovered from the suspending fluid. Bristles removed from the vortexed brushes still yielded confluent bacterial growth on brain-heart infusion agar medium. Virkon (one per cent), Listerine, Cepacol, Scope, and Plax were tested for their bactericidal effects on microorganisms sedimented from the suspending fluid, on toothbrush bristles and proxabrushes, and on various test species including Candida albicans, Mycobacterium smegmatis, M. bovis, and Streptococcus mitis. Virkon and Listerine killed all the test species and virtually all the microorganisms on the toothbrush bristles and proxabrushes. Six volunteers tested the efficacy of a Listerine soaking regime to prevent the bacterial contamination of toothbrushes. Soaking the toothbrush head (bristles) in Listerine for 20 minutes after brushing was sufficient to eliminate bacterial contamination.