I am a retired health care professional and have had constipation since childhood. Worked in GI healthcare for several years and this is the first article that is comprehensive to the point. Recent diagnosis of colonic anertia and the suggestion of colectomy was not the way I wanted to go soI continue to research for an answer. Word of caution to those who use Senna. Senna contains anthraquinone and can cause liver toxicity with long term use. I had been taking Senna daily with the knowledge of my physicians. Two weeks ago I was hospitalized with severe abdominal pain and found my LFT's to be significantly elevated >500. I am certain that the culprit was Senna although the diagnosis was elevated enzymes of undetermined etiology.