Inclusion Criteria:

1. Previously untreated and confirmed histological diagnosis of squamous cell/adenoid
cystic carcinoma of the oropharynx, hypopharynx, larynx, and patients with unknown
primary tumor with metastases to the neck nodes and squamous cell carcinoma of the
skin of head and neck region with ipsilateral neck nodes (more than one node)
metastases.

2. Radiation volume to encompass > or equal to 80% of major salivary glands (parotids
and the non-transferred submandibular salivary gland) and have > or equal to 50 Gys
delivered to that volume via external beam.

3. Karnofsky performance score > or equal to 70

4. Minimum age 18 years

5. The patient must sign a study-specific informed consent prior to study entry

6. Expected survival > or equal to one year

Exclusion Criteria:

1. Carcinoma of nasopharynx, oral cavity, N3 disease, bilateral neck node involvement,
pre-epiglottic space involvement, involvement of level 1 nodes on either side of the
neck, and patients with post-operative recurrent disease.

2. Salivary gland malignancy

3. Salivary gland disease

4. Use of anti-cholinergic drugs and tricyclic drugs

5. Delay in XRT of more than 8 weeks following the curative surgery

6. Pregnant or lactating females are not eligible. Patients of childbearing potential
should agree to use an effective method of contraception

7. Prior head and neck irradiation

8. Recurrent disease

9. Allergy to pilocarpine

10. Patients with uncontrolled asthma, acute iritis, or narrow angle glaucoma