Have you tried slippery elm? It's safe for people with Crohn's. It creates a mucilage when drank with warm water that supposedly coats your guts. I have been using it for a while. I think I have less problems, but I can't be certain. All I know is that it doesn't make me worse or sick and is pretty safe.
http://health.howstuffworks.com/slippery-elm-herbal-remedies.htm