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.