Oral mucositis (inflammation and ulceration of the buccal mucosa) is estimated to occur in 95% of patients diagnosed with head and neck cancer (Trotti et al, 2003; Sonis, 2004). This can be an extremely painful condition, reducing the patient’s ability to take oral analgesia, eat or tolerate fluids. Mount Vernon Cancer Centre introduced Caphosol mouthwash (EUSA Pharma, Oxford) in January 2013. This had a significant effect on the level of analgesia taken by patients, and may contribute to the reduction in the use of opiates in this study.