Mouthwash is a liquid held in the mouth to clean it. There are several types of mouthwash including fluoride mouthwash, which contains fluoride to protect teeth from decay. Antiseptic mouthwash contains alcohol and treats infections and bad breath by stopping bacterial growth. Cosmetic mouthwash is used to freshen breath but does not improve oral health. Natural mouthwash uses ingredients that are safer than other types of mouthwash. Chlorhexidine gluconate mouthwash reduces bacteria and is prescribed to treat gingivitis. The document discusses various types of mouthwash and their purposes.