RATIONALE: Radiation therapy uses high-energy x-rays to damage tumor cells. Drugs such as pilocarpine may protect normal cells from the side effects of radiation therapy. It is not yet known if pilocarpine may be effective in preventing mucositis and dry mouth in patients receiving radiation therapy for head and neck cancer.

PURPOSE: Randomized, double-blinded, phase III trial to study the effectiveness of pilocarpine in preventing mucositis and dry mouth in patients receiving radiation therapy for head and neck cancer.

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.

OUTLINE: This is a randomized, double blind study. Patients receive a central axis midplane dose of radiotherapy five days per week over 6 to 7 weeks. Oral pilocarpine or placebo is administered beginning 3 days prior to radiotherapy, one tablet four times per day for three months. A tablet will be taken 45-60 minutes before radiotherapy. After three months, and after a 3-4 day rest period, all patients receive non blinded pilocarpine for an additional three month period. Patients are followed at weeks 4, 13, and 26 after the start of radiotherapy.

PROJECTED ACCRUAL: A total of 244 patients will be accrued (122 per treatment arm).

DISEASE CHARACTERISTICS: Histologically proven oral cavity and/or oropharyngeal squamous cell carcinoma Radiation volume to encompass at least 50% of parotid glands and have at least 50 Gy delivered to that volume via external beam No salivary gland malignancies or diseases

PATIENT CHARACTERISTICS: Age: 18 and over Performance Status: Karnofsky 60-100% Life Expectancy: Not specified Hematopoietic: Not specified Hepatic: Not specified Renal: Not specified Other: Not pregnant or nursing Effective contraceptive method must be used during study No pilocarpine allergy

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: Not specified Endocrine therapy: Not specified Radiotherapy: No prior radiotherapy to head or neck Surgery: Not specified Other: No concurrent adrenergic antagonists, cholinergic drugs, anti-cholinergics, or tricyclics