I am reluctant to dispute anyone's posts on this site, however I am compelled to provide a word of warning. Senna does not bring the bowel into good rhythm...in fact, it can disrupt the natural peristalsis of the colon. This class of laxatives...pharmaceutical, OTC or herbal...work by irritating the lining of the bowel causing it to expel it's contents. Regular or frequent use of laxatives can result in dependence and weakened bowel muscles, and initiate a vicious cycle of constipation, laxative use and more constipation. As a colon hydrotherapist, I see lots of people who have develped such a dependence and are unable to move their bowels without the use of these laxatives...sometimes for a week or more! Laxatives also do not clean out the older mucoid plaque that accumulates. Just because it's an herb doesn't mean it is safe.