Bad breath, also known as halitosis, is an unpleasant odor that comes from the mouth. It can be caused by various factors, including poor dental hygiene, certain foods, and medical conditions. Bacteria in the mouth break down food particles, producing foul-smelling compounds. Maintaining good oral hygiene, such as regular brushing and flossing, can help prevent bad breath. Drinking water and chewing sugar-free gum can also stimulate saliva production, which helps wash away food particles and bacteria. If bad breath persists, it may be a sign of an underlying health issue that requires medical attention.