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Why Hydrogen Peroxide Shouldn’t Be In Your First Aid Kit
The fizzing may be fun, but it’s not helping you heal
When I was a child, hydrogen peroxide was a staple of our family’s first aid kit. The dark brown bottle contained clear liquid that stung and bubbled when applied to cuts or scrapes. “Don’t worry,” I was told when I complained about the sting. “It kills bacteria, so your wound won’t get infected.”
This statement is technically correct. Hydrogen peroxide does kill bacteria. But current research suggests you should stop putting it on cuts, scrapes, and wounds — and take it out of your first aid kit altogether.
How hydrogen peroxide works
To understand hydrogen peroxide’s mechanism, let’s start with what it is. The formula for hydrogen peroxide is H2O2, meaning that each molecule is made of two hydrogen atoms and two oxygen atoms. Look familiar? The structure is very close to that of water (H2O), but with an extra oxygen atom. That extra atom of oxygen is what triggers hydrogen peroxide’s reactions when it’s poured on cuts (or on potatoes, or on pretty much anything that’s alive). The extra oxygen atom is missing an electron, which it snatches from whatever happens to be nearby.
Though applying hydrogen peroxide to a wound can help kill off any bacteria, it also damages other exposed-but-still-healthy human cells — and can slow healing altogether.
When hydrogen peroxide is applied to a living surface, the oxygen atoms steal electrons from all sorts of vital molecules — including from cell walls and from DNA. By damaging components of bacterial cell walls, the thieving oxygen atoms cause the bacteria to disintegrate.
Another result of applying hydrogen peroxide is a (quite cool) foaming reaction, due to its reaction with a molecule called catalase that our bodies naturally produce. The catalase…
