I hate to say it, but smoking was my 'cure' for IBS. If I were to simply eat and then go somewhere, there would be much uncertainty as to how my stomach would behave on the trip. If I smoke before a trip, I can let my stomach 'do its thing' before I go anywhere - and take care of business before the trip. Before I started smoking, if i had to go then i had to go right then and there - e.g. sides of highways, other peoples homes, nasty public toilets. Then i started smoking and i could control myself.
The flip side of course is that i have chest pains at 23 years old and was completely out of shape up until amonth ago when i started changing things. I took milk out of my diet and am working on quitting smoking. You see, cheese and milk was really the tools IBS used to mess me up, and i used cigarettes to combat IBS. I have since dropped both. We'll see what happens.