Senna is a natural laxative made from the leaves and fruit of the senna plant. It is used to treat occasional constipation in adults and children. Senna works by stimulating the muscles in the gut and irritating the lining of the bowel, which causes a laxative effect. It generally produces a bowel movement within 6 to 12 hours, so it may be taken at bedtime to produce a bowel movement the next day. Senna is available in various forms, including tablets, liquid, powder, granules, and chewable pieces. It is important to follow the directions on the package or prescription label carefully and not take senna for more than one week without talking to a doctor. Senna is also used to empty the bowels before surgery and certain medical procedures.