The Frontal Cortex

Hydrogen Peroxide Doesn’t Work

It was one of those unquestioned rituals of childhood: after getting a little scrape or cut (generally in the knee or elbow area), your mother dutifully applies some hydrogen peroxide to the injury. The peroxide burns, but the pain is just evidence that the peroxide is working. The cut is being cleaned. That, at least, was my childhood understanding of bacterial theory. Only it turns out that hydrogen peroxide isn’t useful at all. In fact, it may actually make things worse:

In a study published in The Journal of Family Practice in 1987, scientists compared the effects of various topical treatments by taking a group of volunteers, administering several small blister wounds on each of their forearms, and then infecting their wounds with bacteria. After applying a different treatment to each wound, they measured bacterial amounts and rates of healing. They found that hydrogen peroxide did not inhibit bacterial growth and that wounds treated with the antibiotic bacitracin healed far more quickly.

Another study, in The American Journal of Surgery, looked at more than 200 people who had appendectomies and found that hydrogen peroxide did not reduce the risk of infection at the site of their incisions.

How long before the empirical facts actually change our habits? My guess is that we won’t stop applying hydrogen peroxide to minor cuts any time soon. The burn lets us pretend that we are doing something, and that’s powerful medicine.


  1. #1 KevinC
    June 19, 2007

    The benefit of hydrogen peroxide is the bubbling, the creation of all that oxygen drives large things out of a deep wound. I would have suspected that it would not work on a small blister like the researchers used. I would use alcohol or anti-biotic cream on a shallow wound.

  2. #2 Roy
    June 19, 2007

    I use hydrogen peroxide as a germicide on fresh fruits and vegetables.

    It does a nice job of detecting where a citrus rind has began forming fungal spores, as it foams immediately even if the spot is too small for the naked eye to see.

    I get 8 pounds of grapefruit a week from a farmers market for $2, and the hydrogen peroxide wash does minimize my losses due to fungus.

  3. #3 kirkmc
    June 19, 2007

    Interestingly, such things seem to be cultural. I grew up in the US, but have lived in France for the past two decades. It was common to put hydrogen peroxide on scrapes when I was a kid, but here they simply don’t use it. They use “real” disinfectants (generally betadine, which contains iodine, and is what is used here in hospitals).

  4. #4 robd
    June 19, 2007

    Never saw it used in the Netherlands either.
    But I have been frequently smeared with iodine.

  5. #5 Brian X
    June 19, 2007

    Oddly enough, I’ve always wondered if such things as hydrogen peroxide don’t do more harm than good. I mean, H2O2 is a very strong oxidizer — shouldn’t it contribute to cell breakdown of native tissue as well as foreign bacteria? (Besides which I have an uncle who is a chronic abuser of the stuff — takes mouthfuls of it straight out of the bottle and uses it as mouthwash. I can’t imagine making a regular habit of that is good for mucous tissue.)

  6. #6 llewelly
    June 19, 2007

    Brian X:

    … I have an uncle who is a chronic abuser of the stuff — takes mouthfuls of it straight out of the bottle and uses it as mouthwash.

    I’m nearly certain I’ve seen H2O2 as mouthwash recommended on many an H2O2 bottle. It seems that in recent years the recommendation has been altered to include (further) dilution with water.

  7. #7 chezjake
    June 20, 2007

    Yes, hydrogen peroxide does kill a few cells when used for wound cleaning. However, the strong oxidation does kill anaerobe bacteria, especially tetanus, as well as bubbling dirt, debris and dead cells from the wound. It should only be used for initial cleaning, followed by TAO, betadine, or the like.

  8. #8 Elizabeth, MD, PhD
    June 20, 2007

    H2O2 was not used for skin cleansing, but in diluted mixes to cleanse mucosal surfaces, ie, mouth / lips — trying to remove clotted blood from injuries in these areas can do more damage.

    Betadine / iodine is used on the intact skin surrounding the wound, not on the wound itself as betadine / iodine will destroy the subcutaneous / vascular cells that you need for internal wound repair.

    Copious normal saline irrigation is best for cleansing a wound; betadine / iodine for the skin around the wound.

    Some wounds should not be closed, but left open and packed with a saline gauze. The fine gauze should be packed into the wound cervices so the debris and dying tissue can be removed when the dressing is removed. The wound packing is usually wet to dry (but it can be moistened just before removal so that there is no further damage by pulling the away healthy tissue.)

    The skin should be cleansed of the betadine / iodine and then covered with a dry dressing because the skin itself does not like to be wet for too long.

    Most likely, more than you want to know…

    When the ‘non-painful’ topical antibiotics came out, people were reluctant to use them because they did not ‘sting’ when applied and, hence, did not seem to be working!

  9. #9 Obdulantist
    June 21, 2007

    H2O2 is used to control microbial activity in hydroponics systems.

  10. #10 woot
    May 15, 2010

    I just don’t agree with this article. Peroxide is cytotoxic to bacteria and fungi. I’d have to see other studies– 200 patients in one study is hardly conclusive. Peroxide 1% mouthwash kills toothache pain. Peroxide works as a topical remedy for fungus.

    All in all, piss poor research here from an otherwise good writer who just isn’t equipped to weigh in on the subject of medicine.

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