See my response to cteavin in the post below. If you're doing the Master-Cleanse alone you need to do something to assist elimination. I recommend colonics or enemas for this or the salt water flush if the others are not an option for you. I don't advise using herbal laxatives. If you are doing the Ultimate Fast...combining the Master-Cleanse with a psyllium and Bentonite colon cleanse...I would not do the salt water flushes if you are having regular eliminations.
Senna definitely produces results...but it comes at a price! It irritates the bowel lining resulting in rapid expulsion and it weakens bowel tone over time results in dependence.