When I was flaring, I used 15 grams of L-Glutamine amino acid powder for months on end.
Now, in remission, I still continue to use it, but at 5g per day - in my protein shake.
From what I've read it helps with long term colonic repair.
P.S. also can be used for diarrhea, 1 heaping teaspoon in some water on an empty stomach.