Will colitis flare up stop me from going on my vacation?

Hope not!: Depends on severity of pain, bloody stools, frequency is bowel movements, and whether you are having fever, chills and other symptoms suggestive of infection/ dehydration.

Depends: You need to discuss an optimal regimen with your managing doctor. If your vacation is a continuous search for the nearest bathroom, you will be frustrated and angry (not good for colitis). Hopefully you can find a combination of medications which will allow lengthy intervals between bathroom trips.