My technical writing teacher told me this during one of his tangents, and I did some research on it myself - even though I should have been doing my homework...but anyway...
The Tooth About Mouthwash
When originally invented, mouthwash had no alcohol in it, and therefore, did not burn the inside of your mouth when used.
It was unpopular, because people didn't feel anything happening, therefore, they were convinced that it must not be working. Due to this, it didn't sell.
So someone came up with the brilliant idea to add an extra inactive ingredient that would cause some sort of reaction and fool people into thinking the product was working.
Enter alcohol. Many mouthwash brands have 20-25%+ alcohol, while most vodka has 40%. Once mouthwash had this extra kick added in, it caught on and became a hot seller. People believed it was working because they could feel their mouths burning as they used it - even though the addition of alcohol was completely unnecessary and added no benefit to the effectiveness of the product.
Contrary to what many people think, alcohol in mouthwash doesn't kill germs better, nor does it make your breath fresher. It actually causes more germs and makes your breath worse!
Alcohol dries out your mouth, causing bad breath. The germs that cause bad breath are anaerobic, meaning "without oxygen". They thrive where there is no oxygen, and saliva naturally contains oxygen, so a drier mouth means less oxygen, which means more germs, which means bad breath.
So the brilliant addition of alcohol to a mouth-germ killer actually makes it less effective than it was before, back when people were convinced it didn't work - when it actually worked better than it does today.
Now, since some people don't like setting their mouth on fire, many brands have began to offer "Better tasting" and "Mild on sensitive teeth and gums" types of mouthwash. Guess what? They have less alcohol in them.
A normal bottle of Listerine has 26.9% alcohol. The Natural Citrus flavor that was advertised as being "Less Intense" has 21.6% alcohol in it, as well as SUGAR, another bad breath mongol.
Some companies even offer a breakthrough in mouthwash technology. "Alcohol-free Mouthwash". Amazingly, they have managed to maintain the same germ-killing power of regular mouthwash, without the nasty alcohol burn. They must be geniuses! I bet somebody made a lot of money off of that patent. And I bet those same companies charge more for this "New and Advanced Formula", because people these days are actually ignorant enough to fall for it.
Funny. First, people were ignorant by not believing that it worked, because they couldn't feel it work. Now, we've become accustomed to the burn, been indoctrinated to believe that alcohol is one of the active ingredients, valiantly slaying all bad breath in its path, and that the pain experienced is "burning away the bad breath". These same types of companies that had the novel idea to add a counterproductive ingredient into their product are now profiting from their deceitful marketing technique by being able to charge a couple extra bucks per bottle for this "kid-friendly", "burn-free" formula. And yes, once again, we are ignorant enough to fall for it.
Heck, I'll admit it. I thought the same thing. When I've used mouthwash, I thought the burning was killing the germs, like the commercials want you to believe. "You can handle it, just a little longer, your mouth will thank you once you're done, okay, you're done - BLECH! Whew!" These types of deceptive advertisements fooled me - that's why this made such an impression on me when my teacher told me - I just had to research it myself and pass the info along.
Makes you wonder what else we're falling for by blindly absorbing such ads.