The purpose of this study is to evaluate the efficacy and safety of tapered KWA-0711 dose in chronic constipation patients.

Inclusion Criteria:

• The patients who experienced fewer than three spontaneous bowel movements per week for more than 6 months prior to the enrollment.
• The patients who experienced one or more of the following signs or symptoms during more than 25% of bowel movements for more than 6 months: straining, lumpy or hard stools, and a sensation of incomplete evacuation

Exclusion Criteria:

• Patients who have secondary constipation caused by systemic disorder.
• Patients who have organic constipation.
• Patients who received intestinal resection.