Hydrogen Peroxide vs. Alcohol

Last night I cut myself and began to clean the wound with alcohol (the standard rubbing alcohol that you buy in a drugstore). My wife saw me cringe as I applied the alcohol to the cut and said that I should use hydrogen peroxide instead because it doesn’t sting. My reply was that, in my opinion, peroxide stings WORSE than alcohol, because it takes longer to evaporate off the skin. I’ve also heard that peroxide doesn’t disinfect as effectively as alcohol.

My question(s), then, are:

  1. Is there a difference in the chemical reactions of peroxide and alcohol when applied to a wound?

  2. Is one any better than the other at cleaning a wound?

  3. Which one stings worse? (I know this is somewhat subjective, but there must be some empirical evidence available)

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“No thanks Roy, I’m stuffed!”


  1. Hydrogen peroxide dissociates into oxygen and water. Alcohol just stings.

  2. If you have an aversion to cleaning your wounds with water, or soap and water, H2O2 has the advantage that the O2 bubbling might dislodge something.

  3. No subjective opinion.

Alcohol does not really do a good job at disinfecting your wound. You’re better off cleaning it with soap and water (if it’s superficial), and dressing it with clean gauze (a bandaid). I use neosporin since my personal experience shows that I get infections when I don’t. My thoughts are that cleaning the wound with alcohol probably kills some skin cells that would be better left alive.

In the old days, they would put this bright purple iodine stuff on it. It stung like a thousand bees. Hydrogen Perox reacts with organic compounds or blood turns white. If it turns white, infection.

Hey, look, ditch all that stuff, get some Betadine at the store. Its expensive, but is one of the most powerful cleaning agents you can buy for this sort of thing. It’s brownish and you can not even feel it when you use it.
Wonderful stuff. Docs use it.

I’m pretty sure hydrogen peroxide will produce white bubbles on any open wound, not just ones that are infected. It’s some enzyme that catalyzes the reaction, not bacteria.

My science education has been refuted enough on this board that I offer this reluctantly. The bacteria that you have to worry about are anaerobic and will die in the oxygen rich environment produced by the the peroxide reaction. I’m sure I’ll be called a fool by the next poster, but that’s how I learned it.

Oh, and as to the original question, I think it stings less than alcohol, but you should be dilluting it before you apply it. It’s way too strong right out of the bottle.

Variously known as Mercurochrome or Merthiolate. (two different brands?). And boy, did it ever!!

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The prevailing medical wisdom of the day for superficial cuts:

Wash with soapy water. (This really doesn’t clean the wound, but makes the surrounding skin less likely to harbor infecting agents.)

Let it bleed a bit. (Blood going out means nothing’s going in. The clotting action will then start to close the wound naturally.)

Once it stops bleeding. Clean again and bandage (to stop it from opening again). Clean and rebandage often and for as long as necessary. Let scabs fall off naturally.

Topical anti-bacterial agents are too late if there already is a wound (and they damage healthy skin moreso than ‘disinfect’ a wound). They’re effective pre-emptively if you need to pop a boil, dig out a splinter, or do surgery. Which disinfectant works best? I’ve heard alcohol over peroxide, however, since both come in different strengths, I’d think that was an overgeneralization.


This is correct. The peroxidase in your blood will decompose hydrogen peroxide and make it bubble up. I’ve never heard that it needed to be diluted though… the hydrogen peroxide that you can get at the drugstore is only a 3% solution in water, and I always just pour it straight on.

Mercurochrome and iodine are two different things, though they’ve both been used as topical disinfectants. I don’t know about methiolate; it’s not listed in the Merck Index I have.

Torq, here you go, Mer·thi·o·late
trademark-- used for thimerosal : a crystalline organic mercurial antiseptic C9H9HgNaO2S used especially
for its antifungal and bacteriostatic properties

– used for merbromin
: a green crystalline mercurial compound C20H8Br2HgNa2O6 used as a
topical antiseptic and germicide in the form of its red solution
Note the bacteriostatic vs germicide. …Static means it prevents development more than kills.also antifungal,and anti septic
Both of them and Iodine are tinctures in alcohol. Alcohol kills (germicide)by physically destroying the structure of the bacteria, and YOUR cells but you cells out number the bactera so no huge loss. Soap works similarlly. Hang your head over and hear Moriah. Alcohol is best used as a prophlactic. H2O2 is an oxidizer, it destroys some bacteria chemically (see the ‘Bleach’ thread for that http://www.straightdope.com/ubb/Forum3/HTML/001988.html all about electrons disapearing and reappearing and all kinds of groovy science stuff,ignore any rude comments i may have made in there)Also it releases it’s own oxygen and acts as an antiseptic Greg was right about those anerobes,there the ones responsible when we say a wound went septic. H2O2 will ‘foam’ when it comes in contact with lots of stuff especially organic,even the ‘dirt’ on your hands…It will ‘disolve’ scabs and that is why it is used to clean old wounds. I never thought it stung much at all. Neo sporin is great stuff.When a big ol mesquite log i was tryin to push thru a band saw jumped up and smashed my face the doc had me use Neosporin on all the wounds, but also shot me full of all kinds of stuff and had me soak the stiches and wounds with hydrogen peroxide.The H2O2 was to keep the stiches clean too.The first two days i was even able to use alcohol, i couldn’t feel a thing any way. Better stop now, i am running out of pixels.

“Pardon me while I have a strange interlude.”-Marx

Betadine and peroxide both inhibit wound healing.

I’m partial to silvadene ointment, especially for burns. Nothing beats it as an antiseptic, but it can promote scarring so you wouldn’t want to use it on a conspicuous place like your face.

Ah, maybe not for you but I usually put one drop of Betadine [a generic equivalent, really @ $8 pint] on a cut and 2 days later its all cleared up. Sometimes Peroxide does the same thing but it feels icky.

Last time the Doc cleaned up a canine bite on my leg they used Betadine scrubber. Cleared it right up, felt great & no further treatment needed.

So, this brings up another question I had. I understand that peroxides readily release oxygen radicals, and I can imagine that they want so badly to combine with something that they end up breaking down the cell walls of germs, but why does alcohol (proponol) do the same? I know that in an o-chem class sense it’s an acid, but a pretty darn weak one. Why does nothing seem to be able to live in alcohol?

Mercurochrome is a brand of iodine solution? Hmm. I always thought it was a solution of mercury and chromium (hence the name).

And then I wondered, “Why the hell would someone want to put mercury on an open wound?! Wouldn’t it get in their bloodstream and give them mercury poisoning?”

I’m not flying fast, just orbiting low.

D’OH! I just saw what mr john wrote. That’ll teach me to read through the whole thread before responding.

I prefer peroxide over alcohol. Someone said peroxide inhibits healing, but I seem to heal faster with peroxide, and it doesn’t sting. (Right from the bottle - no need to dilute it) Now this is with minor cuts. I had a pretty deep cut (sliced my thumb while slicing veggies) and it bled a lot. It didn’t occur to me to dump peroxide or alcohol on it, it was bleeding so bad. I held it under cold running water and let it bleed for about 10 seconds (I have this idea that letting it bleed will wash out some of the bacteria), then wrapped it well with a clean cloth and kept it wrapped til it stopped bleeding. After that, just kept a bandaid on it. Some doc probably would’ve recommended stitches, but after my one experience getting stitches, I don’t go that route.

I like this one product called Medi-Quik.

I think its main ingredients are Lidocaine and Benzalkonium Chloride. I may be wrong on the compound. It doesn’t sting like alcohol, disinfects, and helps form a scab a lot quicker.


Let’s hope my .sig WORKS this time.
Sorry about the extra post =).


Legend (urban legend?)has it that several of the leading over-the-counter antiseptics dropped alcohol years ago, but quickly went back to using the alcohol as an ingredient.

Why? Supposedly, BECAUSE the antiseptics didn’t sting as much when the alcohol was removed! You’d THINK people would prefer antiseptics that don’t cause pain, but (if this legend is true), the OPPOSITE may be true. Millions of people THINK that an antiseptic has to sting to work, and when they applied the alcohol-free salves to a cut, and it DIDN’T hurt, they feared it wasn’t working, and started buying other brands that DID sting (which supposedly “proved” they were working.)

Anyone know if there’s truth to this?

Lidocaine is an analgesic, which may have something to do with why that particular preperation doesn’t sting.

All the stores I go to still sell “rubbing alcohol”, which is isopropanol, the main ingreadient in aftershave. I bet Russians still use it as such for an aftershave. It works on the tiny cuts that are hard to see. H2O2 goes flat in a year or two, alcohol keeps forever

tracer, don’t forget those mercury fillings people get in their teeth. Mercury is fine in small doses.