Listerine(R) Products: An Update on the Efficacy and Safety.

In the 19th century, the mouthwash Listerine(R) was formulated from four essential oils. Later, the oils were replaced by their marker substances. To keep them in solution, 24-27% ethanol was added as a vehicle. This is an update of our previous review on the efficacy and safety of Listerine(R). METHOD: PubMed was searched for clinical studies on the therapeutic benefits and safety of Listerine(R) from the end of 2011 to the end of October 2015. RESULTS: Sixteen studies were found and extracted. Three of the four 6-month studies were of sound confirmatory design. Two of these investigated Listerine(R) and one Listerine Zero(R). The evidence of effectiveness for Listerine(R), based on the bulk of three confirmatory studies and numerous exploratory studies carried out so far, is strong, but only moderate for Listerine(R) Zero and poor for Listerine(R) Cool Blue. In the three safety studies identified, we found methodological flaws that biased the results. CONCLUSIONS: Evidence is accumulating that Listerine(R) is effective in improving oral health, but the absence of systematic toxicological studies means that an accurate safety assessment cannot be made.