The purpose of this study was to determine the extent of bacterial contamination of toothbrushes after use and the efficacy of chlorhexidine and Listerine in decontaminating toothbrushes. The effectiveness of covering a toothbrush head with a plastic cap in preventing contamination was also evaluated. It was found that 70% of the used toothbrushes were heavily contaminated with different pathogenic microorganisms. Use of a cap leads to growth of opportunistic microorganisms like Pseudomonas aeruginosa, which may cause infection in the oral cavity. Overnight immersion of a toothbrush in chlorhexidine gluconate (0.2%) was found to be highly effective in preventing such microbial contamination.