One of the most common and troublesome complications of modern intensive anticancer treatments is oral mucositis. The purpose of this review is to summarize current evidence and clinical guidelines regarding its prevention and therapy. The use of keratinocyte growth factor-1, supplementary glutamine and other recently developed treatment modalities are discussed. The injury of the oral mucosa caused by antineoplastic agents promotes the local expression of multiple pro-inflammatory and pro-apoptotic molecules and eventually leads to the development of ulcers. Such lesions predispose patients to several infectious and nutritional complications. Also, they lead to modification of treatment schedules, potentially affecting overall prognosis. Local cryotherapy with ice chips and phototherapy with low energy laser may be useful as preventive measures. Mouthwashes with allopurinol and phototherapy with low energy laser can be used as treatment. In radiotherapy, special radiation administration techniques should be used to minimize mucosal injury. Pain control should always be optimized, with the use of patient controlled analgesia and topical use of morphine. Supplemental glutamine should not be used outside of research protocols. Lastly, thorough attention should be paid to general care and hygiene measures.