Combined-modality treatment of head and neck cancers, though linked to improved outcomes over earlier treatment methods, can be associated with acute and late adverse effects. These toxicities may lead to significant morbidity, increased mortality, and decreased quality of life. It is necessary to provide patients with adequate supportive-care measures in order to lessen suffering while maintaining the ability to deliver necessary doses of anticancer agents. The current review describes the pathology, assessment, and treatment options for cases of mucositis, impaired swallowing, nutritional and metabolic changes, xerostomia, radiation dermatitis, lymphedema, taste alterations, and pain, all of which may be associated with treatment of patients with head and neck cancers. Additionally, the pretreatment and during-treatment evaluation of dental health, as well as posttreatment dental care, are described.