There are a large number of mouthrinse products available to the general public for use as adjuncts to oral hygiene. Many have not been evaluated and relatively few comparisons of products have been made. This study compared 4 mouthrinse products containing cetylpyridinium chloride (CPC), chlorhexidine, C31G, or triclosan with saline rinse included as a placebo control. Twenty dentate volunteers took part in this 4-day plaque regrowth study which had a single blind, randomized cross-over design balanced for residual effects. On day 1 of each study period, volunteers were rendered plaque free by a professional prophylaxis, suspended normal oral hygiene measures, and rinsed twice daily for 1 minute with 15 mL of the allocated rinse. On day 5, subjects were scored for disclosed plaque by plaque index and plaque area. By both measures the order of decreasing product efficacy was chlorhexidine, CPC and triclosan, C31G, and saline. All the differences in favor of the chlorhexidine product were highly significant as were those in favor of the other rinses compared to saline. It is concluded that the findings of this study reflect the actual chemical benefits of the products divorced from the indeterminate variable of toothbrushing.