I asked Shellycat the same question. this was her reply
It depends on what kind of Crohn's disease she has - they can call things Crohn's with very different patterns. If she has blood, she should avoid fiber for 3 days. Psyllium may not be the best fiber for her, she may need to start out with whole flax seeds for a week or so and then switch to powdered flax seeds.
Crohn's is a bad combination of food allergies
and imbalanced microbes. This is why fasting is such a great protocol for it - you stop the cycle of spasming colon due to allergies, and killing off good microbes due to bad diet. It helps to do a combo MC/veggie juice fast so that the liver is right away helped, bile is cleansed. Toxic bile is one of the co-ffactors of Crohn's.
If no blood, then fiber should be taken in small amounts very regularly every day. All cold drinks and cold foods should be totally avoided - no more iced teas! Warm teas instead. Ginger, peppermint, are especially beneficial, as are enemas/colonics.
After a couple weeks of this protocol, microbes should be introduced, taken for about a month.
That should remove the need for surgery! :)