Intestinal Formulas...damaging?

Dr. Shultze,
I just received Intestinal Formulas 1 and 2 in the mail. I was disturbed to see soo many purging herbs in the list of ingredients. Cascarda and Senna...aren't these all damaging to the colon, kidneys, and intestines when used for period of time...AND habit forming? I was excited about using these after years of battling chronic constipation, but these are the same things that we are told to stay away from and not to use for long periods of time? Could you please explain to me HOW these herbs in this formula work and WHY they WOULDN"T be damaging and/or habit forming after extended perods of use?
Thank-you for any information you can give me. Tweet