I have tried l-glutamine, it is wonderful if you have diahrea, it slows it right down, but it can clog you up if you take it every day.
Slippery Elm root is the best for me. I think it is wonderful stuff. I mix some root with warm water and just drink it. It goes sort of thick, almost like arrowroot. I have even put it in broths when they are cooked, taken off the heat, and mixed a heaped tsp. full in to thicken. When I was very ill with IBD, this was the one thing that helped more than any other, plus it is supplies nutrition which is needed at a time like that. I am positive it gave me the strength to get better, when nothing else had.