The purpose of this study is to evaluate the effectiveness of NGX267 in the improvement of decreased salivary flow associated with primary or secondary Sjögren's syndrome.

For each patient, the study includes four periods of treatment separated by a washout period that may range from 4 - 8 days according to patient and site discretion. Each treatment period includes two overnight stays in the clinic. One dose of study drug is taken during each treatment period

Inclusion Criteria:

• Males and females aged 21 to 55 years, diagnosed with primary or secondary Sjögren's syndrome.
• Patients with a complaint of dry mouth based upon difficulty in speaking, swallowing, a sensation of mouth or throat dryness, lip or tongue dryness, or a level of thirst of sufficient intensity for the patient to seek therapy.
• Females of childbearing potential must not be at risk for pregnancy during the study. Females not of childbearing potential include postmenopausal and women who have been surgically sterilized.
• Patients must not be in an acute phase of illness.

Exclusion Criteria:

• Patients who have clinically significant reduction kidney function. cardiovascular abnormalities; lymphoma secondary to Sjögren's syndrome; pulmonary disease; the presence of enlarged salivary glands; physical closure of the salivary gland or known surgical procedure on the lacrimal punctum.
• Patients with diagnoses of a current gastrointestinal (GI) disease that would be exacerbated by the use of cholinomimetics; a current and acute psychiatric disorder, acute iritis, narrow angle glaucoma, or retinal disease as determined by medical history and physical examination.
• Patients who are otherwise judged inappropriate for inclusion in the study by the investigator
• Patients who have received any experimental drugs or devices or participated in any clinical trial within 30 days prior to screening including participation in a previous NGX267 clinical trial.
• Patients who are allergic to compounds that are similar to NGX267.