Why You Shouldn’t Rinse Your Mouth With Water After Brushing Your Teeth

Spit, don't rinse.
Spit, don't rinse. / PeopleImages/iStock via Getty Images

After you finish brushing your teeth, swishing around some water before spitting ensures that you rid your mouth of all that frothy toothpaste. But as it turns out, having a little toothpaste residue left in your mouth isn’t a bad thing—in fact, it’s an important part of keeping your teeth healthy.

This is because toothpaste contains fluoride. “Fluoride is the single most important ingredient in toothpaste,” Dr. Nigel Carter, dentist and CEO of the UK’s Oral Health Foundation, explained on the organization's website. “It greatly helps oral health by strengthening the tooth enamel, making it more resistant to tooth decay. It also reduces the amount of acid that the bacteria on your teeth produce.”

If you rinse your mouth with water immediately after a brush session, you’re also rinsing away the fluoride, which doesn’t give it much time to work its magic. Instead, many experts recommend simply spitting out excess toothpaste. The Oral Health Foundation even launched a campaign called “Spit, Don’t Rinse” in 2016 to encourage the habit.

The need to completely clear your mouth after brushing can be strong, especially if you’ve rinsed with water for your entire life. Some people rinse with mouthwash as a workaround—but that may not be such a great idea either, since toothpaste has a significantly higher concentration of fluoride than mouthwash does. The UK's National Health Service advises gargling with mouthwash at a different time of day, like after a meal.

Skipping the post-brush water rinse is just one way to improve oral health. Here are seven others.