Why You Should NEVER Use Mouthwash After Brushing

The NHS advises some pretty strict eating rules after using it, too.
Close-up of woman's hand holding cup of mouthwash
Grace Cary via Getty Images
Close-up of woman's hand holding cup of mouthwash

You might already know that it’s not a great idea to rinse your mouth out after brushing your teeth, as this banishes toothpaste’s active ingredient, fluoride, from your gnashers.

And it turns out that mouthwash is no exception. The NHS revealed that you might need to wait for way, way longer than you’d expect before your post-brushing mouth is ready for that minty liquid.

How long exactly?

Of course, you can get mouthwash with fluoride in it, which you would think might undo the fluoride-washing argument.

But, though “using a mouthwash that contains fluoride can help prevent tooth decay,” you shouldn’t “use mouthwash (even a fluoride one) straight after brushing your teeth or it’ll wash away the concentrated fluoride in the toothpaste left on your teeth,” the NHS explains.

And because the ingredients in mouthwash are so strong, you might want to wait for hours after brushing your teeth before using it ― “Choose a different time to use mouthwash, such as after lunch,” they say.

Healthline is a little less extreme, saying, “you may want to wait around 20 minutes after brushing your teeth to use an oral rinse, especially if it contains alcohol or doesn’t contain fluoride.”

But both seem to agree that: “If you apply mouthwash without fluoride directly after brushing with fluoride toothpaste, you could be rinsing fluoride off your tooth enamel, which would do more harm than good.”

What about eating?

The NHS says you should wait 30 minutes to eat after using mouthwash (you know what, I’d follow that advice for the taste implications alone).

They add that adults should use a toothpaste that contains at least 1,350 parts per million (ppm) fluoride, while children under three should use a toothpaste with a minimum of 1,000ppm fluoride.

And, mouthwash or not, it’s important to brush your teeth twice daily (“for about 2 minutes last thing before you go to bed and on 1 other occasion every day,” the NHS says) and floss at least once a day (much further than you’d probably think).

Such demanding bones, aren’t they?