I was diagnosed with lymphocytic colitis 6 yrs ago and last year collagenous colitis was added, as well as diverticulosis so I understand your frustration. I found some relief through diet. I can eat in small amounts cane sugar, pure maple syrup, raw honey, and raw fruit. I cannot eat any gluten (wheat, rye, oat, corn, semolina, tapioca - that is in flour, bread, cake, biscuit, wheat pasta, couscous, beer, malt vinegar). No soy, soya, tofu, soy lecithin, Worcestshire sauce, or MSG. No dairy - milk, cream, butter, cheese, casein, or whey (can handle goat milk). No beans, peas, guar gum, peanuts or cashews. No chicken eggs, duck eggs are no problem for me but they are expensive and hard to come by. No potatoes, tomatoes, eggplant, bell peppers (hot peppers seem to be no problem for me). Raw vegetables e.g. salad which I miss. No high fructose corn syrup or aspartame. The only oils I can tolerate are coconut, olive, and walnut.