OBJECTIVES: I. Determine whether prophylactic use of pilocarpine can shelter unstimulated and stimulated whole salivary flow in patients with head and neck cancer. II. Determine whether prophylactic use of pilocarpine can moderate xerostomia in these patients. III. Determine whether prophylactic use of pilocarpine can reduce the grade and duration of radiation induced mucositis in these patients. IV. Evaluate quality of life outcomes between patients receiving pilocarpine versus placebo. V. Evaluate the impact of xerostomia on patients receiving irradiation to the head and neck.