It depends on a whole lot: your body, environment, food intake, and meds. Your body and meds are probably the most influential factors. I started off on Asacol HD (mesalamine) pills and suppositories, and that took a few days to a week to start working. I can't remember exactly, but it worked well for about 5-7 years. Once that stopped working, I was hospitalized for 2 weeks while they pumped me with prednisone IV to get everything under control. After that, they placed me on Humira (adalimumab). Now, if I miss a Humira dose and flare symptoms come back, they go into remission within a day of the Humira injection.
As far as environment, I have to be completely stress free. No work, no chores, no arguments. This helps speed up remission considerably.
Regarding intake, I eat super bland food with as little fiber as possible. Absolutely alcohol whatsoever.
lol oops! yes, i meant absolutely no alcohol. someone kept interrupting me when i was making that comment and there was a baby that wouldnt stop crying in the background.