Why Does Blood Foam?

Blood foams when treated with hydrogen peroxide because of the presence of an enzyme called catalase, which is found in blood and many other living tissues.

Catalase breaks down hydrogen peroxide into water (H₂O) and oxygen (O₂). The rapid release of oxygen creates bubbles or fizzing.

This reaction, which also creates a ton of heat, is often used in first aid to clean wounds, as it helps to remove debris and kill some bacteria, though it may also damage healthy tissue, which is why it's not always recommended for regular wound care but is amazing for removing blood stains!