Hand sanitizer is a gel or liquid used to reduce germs on the skin, particularly on the hands. It typically contains alcohol, which is effective in killing many types of bacteria and viruses. Hand sanitizer is a convenient alternative to soap and water, especially when they are not available. To use hand sanitizer, apply a small amount to the palm and rub it over all surfaces of the hands until they are dry. It is important to use enough product to cover the entire hand. While hand sanitizer is helpful, washing hands with soap and water is generally more effective for removing certain types of germs.