The purpose of this study is to exploratively investigate the clinical efficacy of rebamipide on dry mouth in patients with Sjögren's syndrome in comparison with placebo.

Inclusion Criteria:

1. Patients with Sjögren's syndrome (Revised Japanese criteria for Sjögren's syndrome (1999): 1998 research report on immunological intractable diseases specified by the Japanese Ministry of Health and Welfare)
2. Patients aged 20 years or older at time of consent
3. Patients with dry mouth
4. Patients with decreased salivation

Exclusion Criteria:

1. Patients who have developed dry mouth clearly due to a cause other than Sjögren's syndrome
2. Patients in whom Saxon test cannot be performed (artificial tooth, tooth implant, etc.)
3. Patients who have received rebamipide within 3 months prior to obtaining informed consent
4. Patients who are pregnant, possibly pregnant, or lactating
5. Patients with a history of hypersensitivity to rebamipide
6. Patients who have received any other investigational drug within 3 months prior to obtaining informed consent
7. Patients who are otherwise judged inappropriate for inclusion in the study by the investigator or subinvestigator

The Efficacy Analysis Set comprised subjects in the Full Analysis Set (subjects received IMP at least once) excluding ineligible subjects and subjects with protocol deviations as described below:

1. Subjects violating the rules on concomitant therapy
2. Subjects with poor treatment compliance (<80% of the prescribed dose at time of treatment discontinuation/completion)
3. Subjects with missing data on the primary endpoint at all time points

Treatment-emergent adverse events were collected from the start of IMP administration up to 9 weeks.

Safety analysis set included all subjects who received investigational medicinal product (IMP) at least once and from whom data on at least 1 safety endpoint were obtained after the start of IMP administration.