A sanitizer is a substance used to reduce or eliminate harmful microorganisms on surfaces or skin. It often comes in liquid, gel, or foam form and is commonly used in settings like hospitals, restaurants, and homes. The active ingredients in sanitizers can include alcohol, chlorine, or quaternary ammonium compounds, which help kill germs effectively. Hand sanitizers, a specific type of sanitizer, are particularly popular for personal hygiene. They are designed to be used when soap and water are not available. Using hand sanitizer can help prevent the spread of illnesses, especially during cold and flu season or in crowded places.