Bisacodyl is used on a short-term basis to treat constipation. It also is used to empty the bowels before surgery and certain medical procedures. Bisacodyl is in a class of medications called stimulant laxatives. It works by increasing activity of the intestines to cause a bowel movement.
Bisacodyl comes as a tablet to take by mouth. It is usually taken the evening before a bowel movement is desired. Bisacodyl normally causes a bowel movement within 6 to 12 hours. Do not take bisacodyl more than once a day or for more than 1 week without talking to your doctor. Follow the directions on the package or on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take bisacodyl exactly as directed. Frequent or continued use of bisacodyl may make you dependent on laxatives and cause your bowels to lose their normal activity. If you do not have a regular bowel movement after taking bisacodyl, do not take any more medication and talk to your doctor.
Summary from MedlinePlus.gov, click for more information.