I have Crohn's in my rectum. I have used Canasa suppositories (the suppository form of Asacol). I would use them immediately before bed, otherwise, I had trouble keeping them in. They also left an awful greasy mess in the toilet the next morning. All in all, not too happy with them. They were prescribed by a new GI and when I went back to my old GI, he didn't think they were the appropriate treatment for my case. I was more than happy to hear this news.
I also had some prescribed by a surgeon that were some special concoction made by the pharmacist at the hospital. I couldn't even get them to stay in, even when i went straight to bed. I just quit using them on my own.
Also, in my experience, they are very expensive, even with insurance.
Good luck!