Listerine® Products: An Update on the Efficacy and Safety

Phytother Res. 2016 Mar;30(3):367-73. doi: 10.1002/ptr.5555. Epub 2016 Jan 12.

Abstract

In the 19th century, the mouthwash Listerine® 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®.

Method: PubMed was searched for clinical studies on the therapeutic benefits and safety of Listerine® 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® and one Listerine Zero®. The evidence of effectiveness for Listerine®, based on the bulk of three confirmatory studies and numerous exploratory studies carried out so far, is strong, but only moderate for Listerine® Zero and poor for Listerine® Cool Blue. In the three safety studies identified, we found methodological flaws that biased the results.

Conclusions: Evidence is accumulating that Listerine® is effective in improving oral health, but the absence of systematic toxicological studies means that an accurate safety assessment cannot be made.

Keywords: Listerine®; dental plaque formation; eucalyptol; gingivitis; menthol; methyl salicylate; safety; thymol.

MeSH terms

  • Dental Plaque / drug therapy*
  • Drug Combinations
  • Gingivitis / drug therapy*
  • Humans
  • Mouthwashes / therapeutic use*
  • Oils, Volatile / therapeutic use*
  • Oral Health*
  • Salicylates / chemistry
  • Salicylates / therapeutic use*
  • Terpenes / chemistry
  • Terpenes / therapeutic use*

Substances

  • Drug Combinations
  • Mouthwashes
  • Oils, Volatile
  • Salicylates
  • Terpenes
  • Listerine