You should quit smoking no matter what for all its ill effects, but according to a just-released report, smoking might actually help with symptoms of ulcerative colitis (1). In fact, patients that quit smoking might actually worsen ulcerative colitis (1).
Don't tell the tobacco companies!
The study also evaluated smoking on Crohn's and found that it aggravates the disease and is a risk factor (1).
1. van der Heide F, Dijkstra A, Weersma RK et al. Effects of active and passive smoking on disease course of Crohn's disease and ulcerative colitis. Inflamm Bowel Dis 2009.