Gentle Sennosides Laxative for Overnight Relief Perdiem Stimulant Laxative Tablets are specially formulated for dependable overnight constipation relief. Using a natural vegetable ingredient, this sennosides laxative works gently to effectively produce a bowel movement in six to 12 hours. Perdiem laxative comes in a convenient tablet form that is easy to dose with no mixing and no mess. Each tablet contains 15 mg sennoside, 45 mg calcium and 5 mg magnesium. Adults and children 12 years and older may take two tablets once or twice daily, and children ages 6 to 11 years may take one tablet once or twice daily.