How Dulcolax Works Dulcolax Suppositories uses Bisacodyl as its active ingredient. Clinically proven & safe, it acts as a laxative that stimulates the bowel muscles to cause a bowel movement that is easily passed & without discomfort. The specially shaped suppository is easy to insert comfortably into the rectum, this is ideal for people who cannot or do not like to swallow tablets. Suppositories are sometimes needed before certain medical procedures even if you do not suffer from constipation. How To Use Dulcolax Suppositories Adults & children aged 10 years & over should use one suppository in the morning only. Not recommended for children under 10. Do not use for more than 5 days & do not swallow. If symptoms persist, consult your doctor.