Mouth care is an integral part of nursing practice. However, it has become a ritualistic and banal activity, a topic of conflicting advice and subjective conclusions from sporadic research. Rarely do experts teach it, and it frequently is delegated to the most junior members of the nursing staff. Many cancer treatments result in unavoidable oral toxicity, and the significant prevalence of oral complications in oncology makes mouth care a particular priority for cancer nurses. The confusion and conflict that surrounds best nursing practice in relation to delivering appropriate mouth care should be redressed. This review article details pertinent research to date regarding oral care, with an aim to clarify intervention options, and to identify and promote best nursing practice.