Hi lorilou, colonic inertia and slow transit colon are the same as I understand it. It is a motility issue where the muscles and/or nerves of the colon do not work properly or at all and the waste is not passed along through the colon for evacuation. I am a sufferer also, and yes, diet doesn't seem to have an effect. I just don't go. Only an enema works. Many times I need to do 2 enemas-back to back and I'm still not empty. And yes, the pain is tremendous. Sometimes it subsides alittle, and I get daring and eat something I want to but shouldn't; then I pay with pain. Have you gone through testing?