Just say no to the Listerine theory. Read the abstract I obtained from PubMed: Caries Res. 2002 Mar-Apr;36(2):93-100. An in vitro oral biofilm model for comparing the efficacy of antimicrobial mouthrinses. Shapiro S, Giertsen E, Guggenheim B. Institute for Oral Microbiology and General Immunology, Center for Dentistry, Oral Medicine, and Maxillofacial Surgery, University of Zürich, Switzerland. Abstract The ability of commercial mouthrinses to reduce total viable counts of mixed microbial populations was examined using a previously developed in vitro model of supragingival plaque. Exploratory experiments aimed at fine-tuning the model indicated that optimal correspondence between in vitro and clinical results for chlorhexidine-containing formulations were obtained at a saliva:medium ratio of 70:30 (v/v); moreover, expanding the microbial population from 5 bacterial species to 5 bacterial species + Candida albicans had no noticeable impact on overall results. The efficacies of 12 different mouthrinse proprietary products containing chlorhexidine, hexetidine, octenidine, Triclosan, plant extracts, or aminefluoride/stannous fluoride vis-à-vis biofilm clearance were compared. All mouthrinses promoted a statistically significant reduction in microbial load compared to distilled water. The herbal- and phenolic-based products were substantially less effective than most chlorhexidine-containing mouthrinses, or mouthrinses containing hexetidine or octenidine. No significant difference between the plaque-clearing plaque-clearing abilities of Listerine and Meridol was observed. Once again, I can only recommend CLINICALLY proven 91% isopropyl alcohol.