# Are peroxide bubbles bacterias' dying breath? **URL:** \ **Category:** Factual Questions\ **Created:** [May 10, 2007, 1:46pm UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537 "2007-05-10T13:46:59Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Biggirl](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/biggirl/32/3294_2.png) [@Biggirl](https://boards.straightdope.com/u/Biggirl)\ **Post date:** [May 10, 2007, 1:46pm UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/1 "2007-05-10T13:46:59Z")
A co-worker just said something I’ve heard many times before: The bubbles that form when you put peroxide on an open wound are all the tiny little germs dying. Alcohol kills germs too, but you don’t get that foaming action with it (although you do get a real nice burning sensation-- maybe it’s the dying germs getting their last revenge). What is actually causing the peroxide to foam? ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [May 10, 2007, 1:53pm UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/2 "2007-05-10T13:53:42Z")
Hydrogen peroxide, H[sub]2[/sub]O[sub]2[/sub] breaks down into water and oxygen. The bubbles are oxygen. The breakdown is accelerated by enzymes, peroxidases, found in saliva. ---
**Author:** ![Biggirl](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/biggirl/32/3294_2.png) [@Biggirl](https://boards.straightdope.com/u/Biggirl)\ **Post date:** [May 10, 2007, 2:00pm UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/3 "2007-05-10T14:00:18Z")
[QUOTE=Squink] Hydrogen peroxide, H[sub]2[/sub]O[sub]2[/sub] breaks down into water and oxygen. The bubbles are oxygen. The breakdown is accelerated by enzymes, peroxidases, found in saliva. [/QUOTE] Why would it break down in an open wound that hasn’t been licked? ---
**Author:** ![August\_West](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/august_west/32/18069_2.png) [@August\_West](https://boards.straightdope.com/u/August_West)\ **Post date:** [May 10, 2007, 2:06pm UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/4 "2007-05-10T14:06:09Z")
There are other enzymes that also cause peroxide to break dowm. Catalase being the one I deal with most often. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [May 10, 2007, 2:06pm UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/5 "2007-05-10T14:06:49Z")
Cells contain peroxidases too. When you bust them, it gets out. Metal ions, iron, copper, manganese etc. also catalyze the breakdown. ---
**Author:** ![Uncommon\_Sense](https://avatars.discourse-cdn.com/v4/letter/u/f9ae1b/32.png) [@Uncommon\_Sense](https://boards.straightdope.com/u/Uncommon_Sense)\ **Post date:** [May 10, 2007, 2:14pm UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/6 "2007-05-10T14:14:22Z")
So the foam is from the guts of the cells (due to the wound) interacting with the Peroxide? If I pour some on clean intact skin it shouldn’t react then? Now, the burning question; What if some got poured on poop? Would it bubble and foam up? ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [May 10, 2007, 2:38pm UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/7 "2007-05-10T14:38:00Z")
[QUOTE=Uncommon Sense] If I pour some on clean intact skin it shouldn’t react then? [/QUOTE] Pretty much, although if you’ve been sweating or have dirt on you, you might get a reaction. Poop contains loads of bacteria, which produce peroxidases, so it’ll foam like it’s 1999. ---
**Author:** ![Biggirl](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/biggirl/32/3294_2.png) [@Biggirl](https://boards.straightdope.com/u/Biggirl)\ **Post date:** [May 10, 2007, 3:05pm UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/8 "2007-05-10T15:05:32Z")
Ah, GQ— where you can find peroxide specialists. I think I’ll let my co-workers continue to believe the bubbles are germs drowning. Who wants to be known as a know-it-all? Plus, I doubt they’d believe me anyway. Thanks guys. ---
**Author:** ![Nametag](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nametag/32/406_2.png) [@Nametag](https://boards.straightdope.com/u/Nametag)\ **Post date:** [May 10, 2007, 4:03pm UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/9 "2007-05-10T16:03:09Z")
[QUOTE=Biggirl] Ah, GQ— where you can find peroxide specialists. [/QUOTE] Ooh, great! my roots need a touch-up! What? ---
**Author:** ![Scubaqueen](https://avatars.discourse-cdn.com/v4/letter/s/c0e974/32.png) [@Scubaqueen](https://boards.straightdope.com/u/Scubaqueen)\ **Post date:** [May 11, 2007, 3:24am UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/10 "2007-05-11T03:24:13Z")
[QUOTE=Biggirl] Ah, GQ— where you can find peroxide specialists. I think I’ll let my co-workers continue to believe the bubbles are germs drowning. [/QUOTE] 'kay… so is it or is it not a reliable disinfectant? ---
**Author:** ![Wile\_E](https://avatars.discourse-cdn.com/v4/letter/w/c37758/32.png) [@Wile\_E](https://boards.straightdope.com/u/Wile_E)\ **Post date:** [May 11, 2007, 4:35am UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/11 "2007-05-11T04:35:55Z")
[QUOTE=Uncommon Sense] So the foam is from the guts of the cells (due to the wound) interacting with the Peroxide? If I pour some on clean intact skin it shouldn’t react then? … [/QUOTE] I’ve had some hydrogen peroxide get on my very dry but intact skin and somehow it works it’s way under my skin and it burns. Perhaps there is a tiny break in the skin that I just can’t see but it actually happens a lot and I hate it. ---
**Author:** ![Ruken](https://avatars.discourse-cdn.com/v4/letter/r/f475e1/32.png) [@Ruken](https://boards.straightdope.com/u/Ruken)\ **Post date:** [May 11, 2007, 5:37am UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/12 "2007-05-11T05:37:40Z")
If you can get a hold of a largish quantity of fresh blood (I saw this done with pig blood,) mixing the blood and H2O2 will produce a rather spectacular foamy result. ---
**Author:** ![Tikki](https://avatars.discourse-cdn.com/v4/letter/t/5daacb/32.png) [@Tikki](https://boards.straightdope.com/u/Tikki)\ **Post date:** [May 11, 2007, 6:12am UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/13 "2007-05-11T06:12:38Z")
[QUOTE=Squink] Hydrogen peroxide, H[sub]2[/sub]O[sub]2[/sub] breaks down into water and oxygen. The bubbles are oxygen. The breakdown is accelerated by enzymes, peroxidases, found in saliva. [/QUOTE] Reading this gave me an Aha! moment. Just last week, I asked my dental assistant if I should rinse with water after I use hydrogen peroxide. She said no and, somewhat puzzled, asked why I was asking. I didn’t want to say, “Because it’s a _chemical._” (I tend to be wary of the stronger ones) so I lamely said, “Because of the bubbles.” Now I know that it’s just water and oxygen, not something akin to battery acid. (Well, not quite battery acid, of course.) Thanks for fighting my ignorance, **Squink!** ---
**Author:** ![Anaglyph](https://avatars.discourse-cdn.com/v4/letter/a/ed8c4c/32.png) [@Anaglyph](https://boards.straightdope.com/u/Anaglyph)\ **Post date:** [May 11, 2007, 6:58am UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/14 "2007-05-11T06:58:14Z")
[QUOTE=Squink] Cells contain peroxidases too. When you bust them, it gets out. Metal ions, iron, copper, manganese etc. also catalyze the breakdown. [/QUOTE] Particularly red blood cells (Erythrocytes) contain loads of catalase. As a side reaction of oxygen transport by hemoglobin, superoxide radicals are produced, if an oxygen molecule steals an electron from the heme iron. To protect the cell, superoxid dismutase converts superoxide radicals to H2O2, catalase converts the H2O2 to O2 and water ---
**Author:** ![PBear42](https://avatars.discourse-cdn.com/v4/letter/p/ecccb3/32.png) [@PBear42](https://boards.straightdope.com/u/PBear42)\ **Post date:** [May 11, 2007, 7:46am UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/15 "2007-05-11T07:46:31Z")
Further to **Scubaqueen** at Post #10. Just what does hydrogen peroxide do which makes it a disinfectant? IOW, why does the bugs hates it [sic]? ---
**Author:** ![Sage\_Rat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sage_rat/32/399_2.png) [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)\ **Post date:** [May 11, 2007, 7:52am UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/16 "2007-05-11T07:52:49Z")
[QUOTE=Tikki] Now I know that it’s just water and oxygen, not something akin to battery acid. (Well, not quite battery acid, of course.) Thanks for fighting my ignorance, **Squink!** [/QUOTE] The contents of a molecule has very little to do with how it will react with your body. Increasing or decreasing the number of atoms in a substance can greatly change its chemical properties, causing things to change from being food to being explosive acid and still being composed of just basic “safe” elements. ---
**Author:** ![Anaglyph](https://avatars.discourse-cdn.com/v4/letter/a/ed8c4c/32.png) [@Anaglyph](https://boards.straightdope.com/u/Anaglyph)\ **Post date:** [May 11, 2007, 8:32am UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/17 "2007-05-11T08:32:37Z")
[QUOTE=Sage Rat] The contents of a molecule has very little to do with how it will react with your body. Increasing or decreasing the number of atoms in a substance can greatly change its chemical properties, causing things to change from being food to being explosive acid and still being composed of just basic “safe” elements. [/QUOTE] For example, take 2 H2 + O2 -\> 2 H2O, hydrogen and oxygen reacting with each other to form water: adding water to a fire will extinguish the fire. Adding hydrogen and oxygen may result in a big explosion! ---
**Author:** ![Dr.Lao](https://avatars.discourse-cdn.com/v4/letter/d/2bfe46/32.png) [@Dr.Lao](https://boards.straightdope.com/u/Dr.Lao)\ **Post date:** [May 11, 2007, 12:48pm UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/18 "2007-05-11T12:48:17Z")
[QUOTE=Tikki] Now I know that it’s just water and oxygen, not something akin to battery acid. (Well, not quite battery acid, of course.) Thanks for fighting my ignorance, **Squink!** [/QUOTE] Hydrogen peroxide is not necessarily safe stuff, but it is safe in household concentrations. At higher concentrations it can be very dangerous stuff. It is highly reactive and explosive. ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [May 11, 2007, 4:07pm UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/19 "2007-05-11T16:07:37Z")
[QUOTE=Uncommon Sense] So the foam is from the guts of the cells (due to the wound) interacting with the Peroxide? If I pour some on clean intact skin it shouldn’t react then? Now, the burning question; What if some got poured on poop? Would it bubble and foam up? [/QUOTE] If you pour it on what the poop made burn, yes, it will bubble and foam. ---
**Author:** ![Alwrong](https://avatars.discourse-cdn.com/v4/letter/a/94ad74/32.png) [@Alwrong](https://boards.straightdope.com/u/Alwrong)\ **Post date:** [May 11, 2007, 4:27pm UTC](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537/20 "2007-05-11T16:27:37Z")
Uh, I have a related question: Why does hydrogen peroxide have a distinct smell? It’s more noticeable after applying it to the skin, but it seems to me that it has a slight smell even when it’s in the bottle. [Next page](https://boards.straightdope.com/t/are-peroxide-bubbles-bacterias-dying-breath/403537.md?page=2)