When hydrogen peroxide comes into contact with a cut or wound, fizzing and bubbling is a common sight. This reaction has a scientific explanation rooted in a fundamental chemical process. The bubbles are a clear indicator of a specific interaction at the cellular level.
Understanding the Bubbling Reaction
Hydrogen peroxide (H₂O₂) is an unstable compound that readily breaks down. It decomposes into water (H₂O) and oxygen gas (O₂). The bubbles observed are pure oxygen gas being released.
This decomposition is significantly accelerated by an enzyme called catalase. Catalase acts as a catalyst, speeding up the chemical reaction without being consumed. One molecule of catalase can convert millions of hydrogen peroxide molecules into water and oxygen each second. Catalase is found in nearly all living organisms exposed to oxygen, including human cells, bacteria, and plant cells.
What the Bubbles Tell Us
The presence of bubbles when hydrogen peroxide is applied indicates catalase activity. When poured on a wound, bubbling signifies catalase released from damaged human cells, such as those in blood and tissues. Some types of bacteria also contain catalase, contributing to the bubbling.
The fizzing reaction shows hydrogen peroxide breaking down in the presence of these biological catalysts. Conversely, if hydrogen peroxide is applied to clean, unbroken skin or a non-organic surface, little to no bubbling will occur because catalase is not readily available. This demonstrates that bubbling is a direct result of the interaction between hydrogen peroxide and the enzyme catalase, not an indication of infection.
Hydrogen Peroxide and Its Uses
Hydrogen peroxide has been widely used as an antiseptic and disinfectant. Historically, it was a common household remedy for cleaning cuts and scrapes, with the bubbling action thought to signify effective disinfection. However, current medical understanding indicates that while hydrogen peroxide kills some bacteria, it can also damage healthy skin cells important for wound healing. This damage can slow healing and increase scarring. For minor cuts and scrapes, many medical professionals now recommend cleaning the wound with plain soap and water instead.
Beyond wound care, hydrogen peroxide has various common household applications. It is used for cleaning and disinfecting surfaces like countertops, cutting boards, and bathroom fixtures. Its bubbling action also helps lift stains from fabrics, carpets, and grout, and it can be used as a laundry brightener for whites. Hydrogen peroxide should be stored in its original dark container in a cool, well-ventilated area, away from heat and combustible materials, as light and heat can cause it to decompose.