Chlorhexidine is an antiseptic that has a broad spectrum effect against both gram-positive and -negative bacteria. Chlorhexidine gluconate oral rinse that contains glycerol, coloring, flavoring, and other compounds has been studied in patients with cancer for the prevention and treatment of mucositis. It is important to note that prophylactic use, before development of mucositis, has a different PEP category than the use of chlorhexidine in patients who already have mucositis symptoms.