 Patients who satisfy inclusion criteria and have given informed consent would be randomized into 3 equal groups given different total doses-50MU, 100MU, 200MU. The total dose will be divided equally and give to each of 4 salivary glands viz. the submandibular and parotid gland bilaterally. For example, if 200MU is to be given in total, 50MU would be given to each gland. Injections would be given via a 25G needle to each gland with ultrasound guidance for better needle placement. One site will be injected per gland. 