 - Subjects must have 3 bowel movements per week for at least 2 weeks but for not more than 12 weeks in the past 6 months prior to randomization confirmed at screening and baseline and the presence of at least one other bowel symptom of constipation in at least 25 of defecations; Hard stools. or complete lack of loose or watery stools, straining during defecation, feelings of incomplete evacuation, abdominal discomfort, bloatingdistension 