How does soap kill bacteria and viruses

It is the most effective thing we know to do. That's why surgeons, for example, scrub their hands so very carefully before they go into an OR. It works, and it works really well. Mayo Clinic Minute: How to properly wash your hands. Journalists: Broadcast-quality video TRT is in the downloads at the end of this post.

Second best is hand sanitizer. When you touch, say, a steel surface with a virus particle on it, it will stick to your skin and hence get transferred on to your hands. If you then touch your face, especially your eyes, nostrils or mouth, you can get infected. And it turns out that most people touch their face once every two to five minutes. Washing the virus off with water alone might work. But water is not good at competing with the strong, glue-like interactions between the skin and the virus.

Soapy water is totally different. Soap contains fat-like substances known as amphiphiles, some of which are structurally very similar to the lipids in the virus membrane. This is more or less how soap also removes normal dirt from the skin. But soap is better because you only need a fairly small amount of soapy water, which, with rubbing, covers your entire hand easily.

Whereas you need to literally soak the virus in ethanol for a brief moment, and wipes or rubbing a gel on the hands does not guarantee that you soak every corner of the skin on your hands effectively enough. So, soap is the best, but do please use alcohol-based sanitiser when soap is not handy or practical.

This article is more than 1 year old. Remember that a germ is what we call any microscopic particle or organism that can make us sick, so this includes viruses and bacteria. Most of the gunk we want to wash off of our hands, whether it be dirt or germs, adheres to us thanks to the oils on our skin.

Destroying the oil with a solvent like alcohol or kerosene will thus remove the associated germs. However, although soaps used in hospitals are often strong, alcohol based versions, alcohol and kerosene are themselves toxic to varying degrees and thus not ideal for frequent in-home use. Imagine smelling like kerosene all day? Luckily, we have soap. Already a subscriber? Sign in. Thanks for reading Scientific American.