system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is the white foamy stuff when you put Hydrogen Peroxide on an infection and why does it become foamy?
gpt
There are enzymes in your blood that attack the peroxide and turn it into water and oxygen. The bubbles are what that looks like. 

As a sidenote, though, you should **not** put peroxide on wounds. It kills germs, but it kills everything else it touches, too, including healthy tissue. And since you have a cut you're letting the peroxide in pretty deep. It'll actually impede the healing. Same goes for alcohol, by the way. 

Warm water and soap are the best thing for a wound. After that, put some antibiotic lotion on it.