The breath-freshening benefits of eucalyptus extract have been touted for decades now, since eucalyptol - an organic compound found in the plant - is an ingredient in some products designed to treat bad breath. However, experts are divided on whether the extract works as well as some think it does to bust halitosis.
On the one had, a recent study published in the Journal of Periodontology found that chewing gum dosed with eucalyptol had a positive effect on oral odor. The authors, a team of scientists from the Osaka University Graduate School of Dentistry, used halimeters, tongue-coating levels and plain old nose power to measure the levels of bad breath before and after chewing the product.
They found that eucalyptus-infused gum reduced halitosis after between four and 14 weeks of steady use. All participants were asked to chew the gum five times a day.
The problem - besides the near constant taste of camphor that the gum is likely to have left in the volunteers' mouth - is that steady gum chewing has been shown to give oral microbes a source of energy, from which they produce aromatic compounds that stink up the mouth.
Also, an older study published in the Journal of Dental Research noted that eucalyptol typically acts as an antiseptic only when mixed with other extracts, like menthol. By itself, eucalyptol's chief use in the body is to reduce mucus production, which is why it can be found in cough drops.
Rather than chewing on eucalyptus-flavored gum, individuals with bad breath may wish to try using a specialty breath freshening rinse that moistens the mouth.