Effect of eucalyptus-extract chewing gum on oral malodor: a double-masked, randomized trial

J Periodontol. 2010 Nov;81(11):1564-71. doi: 10.1902/jop.2010.100249. Epub 2010 Jul 1.


Background: Eucalyptus extracts were found to possess an antibacterial activity against some oral pathogens that produce oral malodor compounds in vitro; however, the clinical effects with respect to oral malodor in humans remain unproven. In the present investigation, a randomized clinical study was designed to test the hypothesis that eucalyptus-extract chewing gum can reduce oral malodor in the general adult population.

Methods: Subjects were randomly assigned to the following three groups: a high-concentration (0.6% eucalyptus extract) group (n = 32), a low-concentration (0.4% eucalyptus extract) group (n = 32), and a placebo group (n = 33). The intake period was 12 weeks. The organoleptic score, level of volatile sulfur compounds (VSCs), and tongue-coating score were recorded at baseline and 4, 8, 12, and 14 weeks. Treatment-to-time interactions among groups were evaluated by repeated-measures analysis of variance (ANOVA) followed by the Games-Howell pairwise comparison test.

Results: Relative to baseline readings, significant reductions in clinical parameters, including organoleptic and tongue-coating scores in the high- and/or low-concentration groups, occurred at 4, 8, 12, and 14 weeks (P <0.05). In addition, group-time interactions revealed significant reductions in the organoleptic score, VSCs, and tongue-coating score in both concentration groups compared to the placebo group (P <0.05).

Conclusions: Eucalyptus-extract chewing gum had long-term effects on the olganoleptic score, levels of VSCs, and tongue-coating score. These findings suggest that eucalyptus-extract chewing gum may reduce oral malodor by decreasing the accumulation of tongue coating.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Chewing Gum*
  • Chromatography, Gas
  • Double-Blind Method
  • Eucalyptus*
  • Female
  • Follow-Up Studies
  • Halitosis / metabolism
  • Halitosis / prevention & control*
  • Humans
  • Male
  • Middle Aged
  • Placebos
  • Plant Extracts / administration & dosage
  • Plant Extracts / therapeutic use*
  • Sulfur Compounds / analysis
  • Tongue / pathology
  • Volatile Organic Compounds / analysis
  • Young Adult


  • Chewing Gum
  • Placebos
  • Plant Extracts
  • Sulfur Compounds
  • Volatile Organic Compounds