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Can You Drink Water After Using Fluoride Mouthwash?

It is not recommended to drink water immediately after using a fluoride mouthwash because it will dilute the benefits. The best practice is to wait at least 30 minutes prior to drinking water to maximize the benefits.

act fluoride mouthwash

The reason why is because when fluoride comes in the form of a mouthwash, it is meant to be used topically. You're not supposed to swallow this and ingest it because its not a systemic product.

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Recommendation is to wait 30 minutes

The fluoride mouthwash manufacturers all seem to mostly agree that you should wait at least 30 minutes before eating or drinking. This means that you shouldn't drink any water for about half an hour after rinsing with it.

We scoured the directions from two prominent fluoride mouth rinse makers, Act and Listerine, which both recommended waiting.

ACT anticavity fluoride mouthwash instructions:

  • vigorously swish 10 milliliters of rinse between your teeth for 1 minute and then spit out

  • do not swallow the rinse

  • do not eat or drink for 30 minutes after rinsing

Listerine total care anticavity fluoride mouthwash instructions:

  • Vigorously swish 10 mL (2 teaspoonfuls) of rinse between your teeth for 1 minute and then spit out

  • Do not swallow the rinse

  • Do not eat or drink for 30 minutes after rinsing

What does research say?

Scientific research supports waiting to eat or drink after any type of fluoride treatment. The reason is because most of these treatments are topical in nature and not systemic.

There was a study in The American Academy of Pediatric Dentistry, which compared the consequences of waiting 30 minutes vs no wait. They measured the amount of residual fluoride that was on the subjects teeth over the course of 21 days.

  • The group that rinsed immediately after fluoride application, retained significantly less fluoride on their teeth.

  • The group that waited 30 minutes before rinsing, had a lot more residual fluoride on their teeth.

The chart below shows the difference between rinsing right after vs waiting prior to rinsing. They measured the amount of fluoride that remained on the teeth after 30 mins, 3 days, 7 days, 14 days, and 21 days.

chart - residual fluoride on teeth with and without rinsing
Credit: George K. Stookey, Bruce R. Schemehorn, Catherine A. Drook, Becky L. Cheetham

The conclusion was that topical fluoride works based on being in direct physical contact with the enamel. The longer you leave it there, the more time it has to strengthen and repair them. If you eat or rinse immediately afterwards, you'll still have some of the fluoridated effects but a lot less than if you simply waited!


Benefits of waiting before drinking water

Waiting to drink water will permit the fluoride from the mouth rinse to stay on your teeth longer. If you look at the chart above the no post-treatment rinse had significantly more fluoride in their teeth. This means that those who wait will reap the benefits of fluoride.

critical ph of hydroxyapatite and fluorapatite
Credit: Adam hellen

How fluoride helps your teeth:

  • Strengthens teeth. It can convert the tooth mineral, hydroxyapatite into fluorapatite which moves the critical pH from 5.5 to 4.5 making it more acid resistant.

  • Repairs teeth. Demineralized tooth structure more readily takes up fluoride. It then pulls in calcium and phosphates in order to initiate remineralization.

  • Protects your enamel. It forms a calcium fluoride-like layer that coats the surface of the enamel. This extra layer serves as a sacrificial layer that dissolves first under acid attacks.

  • Antibacterial. The presence of fluoride interferes with the uptake and metabolism of sugar for bacteria. They will eventually starve to death if they take up too much of this mineral.

  • Decreases sensitivity. Stannous fluoride or fluoride varnish can decrease teeth sensitivity by occluding dentinal tubules.


Doesn't tap water already have fluoride?

Your water supply may already have fluoride in it if you live in a fluoridated community. There is a good chance that it does contain it since 73% of Americans have access to it since 2018.

However just because the water that you're drinking has fluoride, it doesn't mean that you should drink it after rinsing with a fluoride mouth rinse. The reason is because the mouthwash has a significantly higher concentration of it than your tap water.

  • The recommended level of water fluoridation is 0.7 ppm according to the CDC.

  • The mouthwash has 0.5% fluoride which is equivalent to 5000 ppm.

Yes the water that you drink may have it but it is not as concentrated. Therefore if you do drink water after rinsing, it will dilute the effects of the mouthwash.

If I don't care about the benefits, can I drink water?

If you really don't care about maximizing the benefits of your fluoridated mouthwash then of course you can drink after. After all there are no physical limitations that are stopping you from doing so. You can eat and drink all you want if you truly desired so.

However if you do so, you wouldn't be getting the most value out of using a mouth rinse. It could work so much better but you're stopping it short. What this is akin to doing is ordering food at a restaurant but only taking a bite before throwing it away.


Drinking water immediately after rinsing with a fluoride mouthwash will decrease its efficacy by diluting the benefits. It's best to wait at least 30 minutes before drinking and eating after rinsing with it in order to reap the full benefits. Studies have shown that being patient will help retain a lot more of the fluoride on your enamel if you do so.

However we just want to point out that if you wait even longer than 30 minutes you can continue to extract benefits from it. It's just that the half hour mark is a good practical point to stop the treatment. Who wants to fast for 24 hours after using a fluoride mouthwash said no one ever!

Of course, our dentists in Long Island City recommend waiting before drinking water after using fluoride mouthwash. It is an important part of your oral hygiene and preventative dentistry.


David Chen 200 x 200.jpg

About the author: Dr David Chen, DDS

Hello, I'm Dr Chen and I'm an actively practicing dentist in Long Island City, NY. I graduated from Columbia University College of Dental Medicine in 2016 but prior to going to dental school I was already working in the dental field. It's been more than a decade since I first got to know dentistry and let me tell you, time flies by quickly. Since then I've developed a fondness for writing, which is how this all got started!

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Medical Disclaimer:

This blog is purely meant for information purposes and should not be used as medical advice. Each situation in your mouth is unique and complex. It is not possible to give advice nor diagnose any oral conditions based on text nor virtual consultations. The best thing to do is to go in person to see your dentist for an examination and consultation so that you can receive the best care possible.

The purpose of all of this oral health information is to encourage you to see your dentist and to inform you of what you may expect during your visit. Due to the unfortunate nature of dentistry, there isn't really any true home remedies that will get rid of dental problems. Roughly 99.99% of them require in-person intervention by a healthcare professional.

Hint: That is the reason why you can't eliminate seeing dentists in your life!

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