The reason peroxide or hydrogen peroxided fizzes when on cuts is because of the reaction with the blood, skin cells causing the hydrogen peroxide to breakdown into water and oxygen.
The resulting oxygen is why the peroxide fizzes on cuts.
When the hydrogen peroxide is poured onto a cut or scrape the hydrogen peroxide then encounters blood and damaged skin cells.
These contain an enzyme called catalase, which breaks down the hydrogen peroxide into water and oxygen.
The fizzing you see in the form of bubbles is the oxygen gas escaping.
When you dab hydrogen peroxide on a cut, that white, fizzling foam is actually a sign that that the solution is killing bacteria as well as healthy cells.
Hydrogen peroxide is a chemical compound with the formula H ₂O ₂.
In its pure form, it is a very pale blue liquid, slightly more viscous than water.
It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution in water for consumer use, and in higher concentrations for industrial use.
Hydrogen peroxide is used to disinfect tools, bleach hair, and to clean surfaces.
It's also used in oral care and gardening.
It may be discomforting to know that a touted skin treatment can also be used as a household cleaner.
Hydrogen peroxide is safe for most people if they use it correctly.
However, the compound can be harmful if a person uses it too often or if the concentration is too strong.
People should never gargle with food-grade hydrogen peroxide, which has a concentration of 35 percent.