Objective: To test in vitro the anti-plaque/ antimicrobial efficacy of a new toothpaste formulation containing a 2% zinc citrate/ 0.3% Triclosan antimicrobial system compared with a 0.75% zinc citrate/ 0.3% Triclosan system and where appropriate, against controls of a standard fluoride paste and a 0.3% Triclosan/ 2% copolymer product. Methods: The anti-metabolic activity was assessed using a range of assays measuring the ability of the active systems to inhibit bacterial glycolysis. The antibacterial/ anti-plaque activity was assessed in an in vitro multispecies biofilm assay. Results: Both zinc formulations were shown to have significantly superior activity at inhibiting glycolysis compared with the 0.3% Triclosan/ 2% copolymer formulation and the standard fluoride paste, particularly in reducing the pH drop after sugar challenge, the new formulation having the greatest activity. Likewise, in the antibacterial assay, both zinc formulations were found to have significantly superior activity over a standard fluoride paste and the 2% zinc citrate/ 0.3% Triclosan formulation was shown to be significantly better than 0.75% zinc citrate/ 0.3% Triclosan formulation. Conclusion: These data provide support for the enhanced performance of the 2% zinc citrate/ 0.3% Triclosan formulation.