Hand sanitizer (also known as hand antiseptic, hand disinfectant, hand rub, or handrub) is a liquid, gel, or foam used to kill viruses, bacteria, and other microorganisms on the hands.[3][4] It can also come in the form of a cream, spray, or wipe.[5] While hand washing with soap and water is generally preferred,[6] hand sanitizer is a convenient alternative in settings where soap and water are unavailable. However, it is less effective against certain pathogens like norovirus and Clostridioides difficile and cannot physically remove harmful chemicals.[6] Improper use, such as wiping off sanitizer before it dries, can also reduce its effectiveness, and some sanitizers with low alcohol concentrations are less effective.[6] Additionally, frequent use of hand sanitizer may disrupt the skin's microbiome and cause dermatitis

Alcohol-based hand sanitizers, which contain at least 60% alcohol (ethanol or isopropyl alcohol), are recommended by the United States Centers for Disease Control and Prevention (CDC) when soap and water are not available.[8] In healthcare settings, these sanitizers are often preferred over hand washing with soap and water because they are more effective at reducing bacteria and are better tolerated by the skin.[9][10] However, hand washing should still be performed if contamination is visible or after using the toilet.[11] Non-alcohol-based hand sanitizers, which may contain benzalkonium chloride or triclosan, are less effective and generally not recommended,[9] though they are not flammable.