Available evidence for treating pain caused by mucositis (inflammation of the digestive tract's lining) and stomatitis (mucositis involving the mouth) can be categorized into two general categories, depending on whether or not the stomatitis is related to cancer therapy (either chemo-or radiation therapy). This chapter addresses cancer treatment-associated stomatitis (CTAM). For CTAM that does develop, pain can be severe and opioids are the therapeutic mainstay. In fact, CTAM pain often necessitates IV morphine and even hospitalization and institution of a PCA regimen. Local anesthetics such as tetracaine or lidocaine are often recommended for CTAM, but their utility is not definitively demonstrated. Most of the data dealing with non-CTAM mucositis addresses aphthous ulcer (AU) treatment. Topical sucralfate is an example of an approach that is not successful in CTAM but found useful in AU. The chapter concludes with an overview of the evidence, lesser in quality and quantity, addressing non-CTAM stomatitis.