Purpose The purpose of this project was to evaluate research in basic oral care interventions to update evidence-based practice guidelines for preventing and treating oral mucositis (OM) in cancer patients undergoing radio-or chemotherapy. Methods A systematic review of available literature was conducted by the Basic Oral Care Section of the Mucositis Study Group of MASCC/ISOO. Seven interventions-oral care protocols, dental care, normal saline, sodium bicarbonate, mixed medication mouthwash, chlorhexidine, and calcium phosphate-were evaluated using the Hadorn (J Clin Epidemiol 49: [749][750][751][752][753][754] 1996) criteria to determine level of evidence, followed by a guideline determination of one of the following: recommendation, suggestion, or no guideline possible, using Somerfield's (Classic Pap Cur Comments 4:881-886, 2000) schema.Results Fifty-two published papers were examined by treatment population (radiotherapy, chemotherapy, and hematopoietic stem cell transplant) and by whether the intervention aimed to prevent or treat OM. The resulting practice suggestions included using oral care protocols for preventing OM across all treatment modalities and age groups and not using chlorhexidine mouthwash for preventing OM in adults with head and neck cancer undergoing radiotherapy. Considering inadequate and/or conflicting evidence, no guidelines for prevention or treatment of OM were possible for the interventions of dental care, normal saline, sodium bicarbonate, mixed medication mouthwash, chlorhexidine in patients receiving chemotherapy or hematopoietic stem cell transplant, or calcium phosphate. Conclusions The evidence for basic oral care interventions supports the use of oral care protocols in patient populations receiving radiation and/or chemotherapy and does not support chlorhexidine for prevention of mucositis in head and neck cancer patients receiving radiotherapy. Additional welldesigned research is needed for other interventions to improve the amount and quality of evidence guiding future clinical care.