A very interesting and informative article from the Michigan Live blog called Spices, herbs make move to medicine cabinet contained this quote about tumeric:
Here is a link they also provide in the artlice to the US National Library of Medicine's MedLine Plus site.� Interestingly, while the site can't claim any proof that the ingredient in Tumeric does have anti-inflamitory properties, there does seem to be some evidence.� However they do note that it can be irritating to the stomach in large doses.�
I would imagine that for a Crohn's patient the trick would be to try cooking Tumeric in a smaller amount into some nice bland rice and see how it effects your digestion.� It is not a particularly "spicy" spice, in and of itself but is typically combined with other spices in curries and spice blends.
Here is a nice Aromatic Yellow Rice recipe from India Snack that might be a nice way to try the benefits of turmeric and its active ingredient curcumin.
Turmeric Root
photo - Wikipedia