Deodorants are personal hygiene products designed to prevent unpleasant body odor caused by bacterial breakdown of sweat. They are typically applied to the underarms, although some deodorants can be used on other parts of the body as well. Deodorants work by either killing the bacteria that cause body odor or by neutralizing the odor itself. Some deodorants also contain antiperspirant ingredients, which help reduce the amount of sweat produced by blocking the sweat glands.