I suffered for about 5 years with appaling stomach cramps and vomiting. The doctors were hopeless, and I tried various drugs, such as anti spasmodics, but nothing worked. Peppermint pills (colpamin) eased the symptoms, but it was usually 8 hours of suffering waves of pain.
As a last resort a friend did a kinesiology test on me, and identified several foods that she said I was intolerant to. These turned out to be tea (i drank about 20 cups a day!), red peppers, and a few other things. Willing to try anything I cut these foods out, and also drank more water. I haven't had an attack since, and that was 2 years ago.
I would recommend that anyone suffering from ibs symptoms to check intolerances first. Either a nutritionalist or kinesiologist can do this for you, or you can test yourself.