eli5 : how/why does hydrogen peroxide react with blood and fizz?

Question

eli5 : how/why does hydrogen peroxide react with blood and fizz?

In: 9

Answer 1

Hydrogen peroxide would normally be poisonous, like bleach. But it also forms naturally in mitochondria as a side effect of using oxygen to make energy. To avoid getting poisoned, organisms that make energy with mitochondria make an enzyme called catalase that turns hydrogen peroxide harmless by turning it into water and oxygen.

You have mitochondria, so you have catalase throughout your body. When hydrogen peroxide reaches the catalase in your blood, it breaks down into water and bubbles of oxygen.