Bacteria: Good vs. Bad

Hello Dr. Ellie,

I’ve been enjoying your blog for a while and am fascinated by your System. I haven’t started using the whole system. I have been taking xylitol after eating, drinking, etc. I have been rinsing with a 0.05% Sodium Fluoride Oral B rinse (ACT isn’t available in Canada, and I haven’t found Fluorgard here either), and have been using Crest Original toothpaste. My hygienist said “I wish everyone took as good care of their teeth as you have.”

However, I am curious about the Listerine part of the System. If Listerine is anti-bacterial, when you rinse with it, won’t it kill the good bacteria along with the bad bacteria? If I’m already getting rid of the bad bacteria with xylitol, allowing it to be replaced with good bacterial, then wouldn’t I be killing all that good bacteria with the Listerine?

Thanks very much for your help!


Hi A,

I understand your concern about the interplay between healthy(good protective) bacteria and unhealthy (cavity and disease forming) bacteria on teeth and the oral cavity. This is one of the reasons I believe we need to assess if regular dental cleanings are always necessary at dental visits. This is also the reason I am against the use of baking soda which appears to upset healthy oral ecology.(You can read more about the danger of unnecessary “cleanings” in Kiss Your Dentist Goodbye” chapter on plaque!)

A huge number of people have used my rinse system for many years. We have all found that our oral health does nothing but improve, year after year. Research on Listerine is extensive it is the oldest of all the oral mouth rinses with origins in the early 20th century! Some research looked at the possibility of “resistant” or unexpected bacteria developing over time and found this did not occur.

The antibacterial properties of Listerine depend on essential oils it contains which ( not surprisingly) are specific to their target bacteria. They have found Listerine does NOT wipe out ALL bacteria, but only immature “cocci” cells precursors of plaque. This is why Listerine has no effect on getting rid of mature (periodontal) bacteria or on healthy bacteria in the mouth.

Xylitol is similarly focused in its antibacterial effects. Xylitol is specifically absorbed by cavity forming Strep mutans bacteria. Once absorbed, the bacterium cannot process xylitol. This causes the cell to expend energy trying to expel xylitol from its system. As cavity forming bacteria disappear, ‘xylitol resistant” bacteria colonize teeth in place of them. These new bacteria are not sticky and do not form plaque deposits!

Research shows that xylitol develops a healthy ecology in the mouth. I hope one day researchers will do a long term test on my system to evaluate the oral ecology that develops because it is this ecology that keeps teeth and gums healthy year after year!

Best Wishes and thanks for your message,

26 Corporate Woods
Rochester, NY 14623

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