White Stringy Stuff In Mouth After Brushing Teeth: What Is It?

Written & Reviewed by Dr David Chen

Do you ever get this white film or white stringy stuff in the mouth after brushing your teeth and you wonder what it is? It’s a bit of a mystery because there is no official explanation as to what it is but we do have a theory as to what it could be based on our experiences.

Just to be clear, it’s not harmful by any means so don’t stress out about it!

risewell toothpaste - what it looks like on toothbrush

When the white stringy stuff appear

In our experience, we’ve noticed that after we brush with certain toothpastes, white stringy stuff or a white film would form in the mouth. This soft sticky substance would all of a sudden appear about 30-60 minutes after you finish brushing.

Description of what it looks like:

  • White stringy stuff
  • White film
  • Soft and easily pliable

Location of occurrence:

  • Along inside of cheeks.
  • On the lips.
  • On the dorsum of the tongue.

This white film in the mouth doesn’t appear immediately but usually a couple of minutes afterwards. It also does not seem to happen with every type of toothpaste, only certain ones.

Scientific studies about it

We’ve scoured all of the scholarly journals but could find no answer as to what the white film in the mouth could be.

Searching on the internet also yielded no results. Some people allege that it could be oral thrush but based on it’s clinical presentation it is definitely NOT of fungal origins.

What it could be

Our theory is that this white stringy stuff in the mouth after brushing is actually biofilm. In other words, it is actually a thin film of plaque which is full of bacteria that have aggregated together to form this sticky substance.

The reason the white film forms in your mouth after brushing is due to antibacterial agents and tartar control ingredients within your toothpaste. We believe it is most likely because of either stannous fluoride or pyrophosphates in toothpaste.

Essentially what happens is that those two ingredients prevent the bacteria and plaque from forming onto the surface of your teeth.

  • Under normal circumstances the plaque would form and stick onto your enamel.
  • However, when you brush with these two agents, the plaque is inhibited from sticking onto the tooth surface.
  • Instead, the plaque will form and adhere to your cheeks, lips, and tongue instead.

Ultimately, since you brushed with this toothpaste, the bacteria can’t adhere to the surfaces of your tooth. Although the other soft tissues in your mouth can still permit the plaque to adhere to it. That is why you get this sticky white film not on your teeth but elsewhere in your mouth.

Stannous fluoride prevents bacterial adhesion

Stannous fluoride (SnF2)is a more premium version of fluoride when compared to the typical sodium fluoride (NaF). We say that because it cost a lot more and the reason it does is because it has a lot of antibacterial properties to it.

Additional benefits of SnF2:

  • Anti-bacterial. It is both bacteriostatic (prevents growth) and bactericidal (kills them).
  • Improves gum health. It reduces gingivitis, gum bleeding, plaque, and bad breath.
  • Decreases teeth sensitivity. Occludes dentinal tubules which reduces sensitivity.
  • Prevents bacterial adherence. It significantly reduces the amount of bacteria adhering to the enamel surfaces of teeth.

Apparently the anti-adherence property of stannous fluoride is all due to the stannous ion. It is this anti-stickiness effect that causes the plaque (white stringy stuff) to form in the mouth but not on the teeth.

Pyrophosphate prevents tartar formation

Pyrophosphates are used as pH adjusters and for tartar control in toothpastes.

  • pH adjusting. Essentially what this does is raise the pH of the toothpaste so that it can function better. No one wants to brush with an acidic dentrifice.
  • Tartar control. What pyrophosphates do is inhibit calcium phosphate deposits from forming on the tooth surface. Essentially, plaque plus calcium and phosphate will result in hard tartar. The pyrophosphates prevent that reaction from occurring.

There are many different types of pyrophosphates used in toothpaste but they all function in the same manner. Some popular ones are tetrasodium pyrophosphate and disodium pyrophosphate.

Is it really not because of SLS?

Based on our experience, the white film in mouth after brushing teeth is definitely not due to SLS (sodium lauryl sulfate). SLS is a surfactant that helps the toothpaste lather and foam for a better cleaning experience.

Colgate baking soda with peroxide toothpaste

The reason we say the white stringy stuff isn’t due to SLS is because we’ve used toothpastes with it and never had it happen. Most recently, we just went through two 8 oz tubes of Colgate baking soda peroxide whitening toothpaste and never had the white substance appear in our mouths.

Once again, this only occurs with certain toothpastes.

As you can see in the ingredient list above, it does have SLS but what it doesn’t have is stannous fluoride nor any pyrophosphates.

Now, where we did experience the white film in our mouths after we finished brushing was with the Colgate Total Plaque Pro Release toothpaste. A white stringy substance would appear within an hour after we finished brushing.

Colgate total pro plaque release toothpaste

Now if you take a look at it’s ingredient list, you’ll notice the presence of stannous fluoride and tetrasodium pyrophosphate. Yes, it does have SLS but we’ve already ruled that out.

Colgate total plaque pro release
Ingredient list

Is it harmful?

Despite the white stringy stuff being biofilm and filled with bacteria, it isn’t harmful because bacteria are naturally present in your mouth. As a matter of fact, the bacteria which have formed the film were pre-existing in your oral cavity.

In other words, it’s the same exact bacteria that your mouth already has.

To be clear, it isn’t harmful even if you swallowed this because the extremely potent and acidic stomach acid would decimate the biofilm. Yes, it would literally get digested and would not survive through your digestive tract.

Therefore, it is safe to leave it as is in your mouth even if you don’t wipe it away.

How to prevent it

There are two methods for preventing this white film in your mouth after you brush. You either drink more water or switch to a different toothpaste.

  • Stay hydrated. We’ve noticed that when our mouths were dry, the sticky white stuff formed more readily. However, if we stay hydrated by drinking enough water throughout the day, it was less likely for it to form.
  • Different toothpaste. Of course if you didn’t want to deal with this condition at all you can simply switch to another toothpaste.

Once again, this only occurs with certain toothpastes and our theory is that you should avoid the ones with stannous fluoride and pyrophosphates. Nonetheless, we still recommend drinking enough water because dry mouth isn’t good for you regardless.


In summary, the white stuff that you’re seeing in your mouth after you finish brushing is biofilm. This is plaque that would’ve otherwise adhered to your teeth but due to the antibacterial properties of your toothpaste it wasn’t able to do so.

What it did instead was form on your cheeks, lips, or tongue.


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