Considerable progress in research and clinical application has been made since the original guidelines for managing mucositis in cancer patients were published in 2004, and the first active drug for the prevention and treatment of this condition has been approved by the United States Food and Drug Administration and other regulatory agencies in Europe and Australia. These changes necessitate an updated review of the literature and guidelines. Panel members reviewed the biomedical literature on mucositis published in English between January 2002 and May 2005 and reached a consensus based on the criteria of the American Society of Clinical Oncology. Changes in the guidelines included recommendations for the use of palifermin for oral mucositis associated with stem cell transplantation, amifostine for radiation proctitis, and cryotherapy for mucositis associated with high-dose melphalan. Recommendations against specific practices were introduced: Systemic glutamine was not recommended for the prevention of gastrointestinal mucositis, and sucralfate and antimicrobial lozenges were not recommended for radiation-induced oral mucositis. Furthermore, new guidelines suggested that granulocyte-macrophage-colony stimulating factor mouthwashes not be used for oral mucositis prevention in the transplantation population. Advances in mucositis treatment and research have been complemented by an increased rate of publication on mucosal injury in cancer. However, additional and sustained efforts will be required to gain a fuller understanding of the pathobiology, impact on overall patient status, optimal therapeutic strategies, and improved educational programs for health professionals, patients, and caregivers. These efforts are likely to have significant clinical and economic impact on the treatment of cancer patients. Cancer 2007;109:820-31. (c) 2007 American Cancer Society.