Sanitizer, also known as hand sanitizer or hand rub, is a solution or gel that is applied to the hands to reduce the number of infectious agents on them. It is commonly used as a supplement or alternative to hand washing with soap and water, particularly in situations where hand washing facilities are not readily available.

The active ingredient in most hand sanitizers is alcohol, typically in the form of ethanol or isopropyl alcohol. These alcohols are effective at killing a broad spectrum of bacteria, viruses, and fungi by denaturing their proteins and disrupting their cell membranes. Some hand sanitizers may also contain other active ingredients, such as benzalkonium chloride, which is effective against certain types of bacteria and viruses.

Hand sanitizers are typically available in a variety of forms, including liquid, gel, foam, or spray. They are applied to the hands and rubbed thoroughly, covering all surfaces of the hands, fingers, and nails, until they are dry. It is important to use hand sanitizer correctly and in the appropriate amount to ensure effective sanitization.

While hand sanitizer is an effective tool for reducing the transmission of infectious agents, it is not a substitute for proper hand washing with soap and water. Hand washing is still considered the best way to remove dirt, grime, and certain types of pathogens from the hands.