Oral complications, such as mucositis inflammation of the mucous membrane which can also cause mouth ulcers, are among the most common problems associated with chemo - and radiotherapy. However, nurses often carry out oral healthcare in a ritualised manner, without regard to patients’ individual needs. Nurses struggle to assess a healthy mouth and are uncertain about which oral health regimes to follow, not least because information on products is conflicting. By reviewing existing literature, this article outlines the need for oncology nurse training in the assessment, prevention and treatment of oral mucositis.