The official word on marijuana from the Crohn's and Colitis Foundation is:
"Today, patients have access to more medications than ever -- medications capable of controlling symptoms and dramatically improving quality of life. CCFA's expert consensus remains: The harmful side effects of marijuana far outweigh its potential benefits. In other words, until a new cannabinoid-based drug comes to market, don't go there." http://www.ccfa.org/about/news/medicalmarajuana
The following link takes you to interesting quotes from research both pro and con the use of pot: http://medicalmarijuana.procon.org/viewanswers.asp?questionid=000138
You could try the introductory version of the SCD diet for a week or so and see whether it helps. More info at www.breakingtheviciouscycle.info