There are some chemotherapy drugs used in the treatment of crohn's disease - like methotrexate. However, in crohn's disease, just like in Rheumatoid Arthritis, chemotherapy drugs are used in very low doses, to suppress immune system, to prevent flare ups. Definitely not in the high doses used for chemotherapy, so the side effects are much reduced.
I hope this is what you were looking for.
Husband with Crohn's
Diagnosed March 2003 Ulcerative Proctitis
Diagnosed March 2008 Crohn's & C-diff, hospitalized 45 days
Crohn's in Remission since June 2008
C-diff recurrence Sep 2009
Reactive Arthritis Nov 2009
Currently c-diff free
Osteopenia of spine (Mar 2010)
Canasa (1gm), Lialda (4.8 gms), Remicade (8 weeks)
Currently In Remission