First a little about my situation, I suffered the extremely painful bowel movements that went away almost imediatly my wholelife so I thought it was natural then 10 years ago the cramps came and didn't go away so I knew something was wrong, I began a search and tried all the usual cures, then I found a calcium that works here, caltrate D, chewables, I have been basically pain free for over a year. Last year I went on a health kick and 3 months ago I started taking centrum ultra mens over 50 vitamins, everything went wellI ran out 2 weeks ago and bought a new batch, but since I am not over 50 I just bought the regular mens ultra, about 2 days later I started having pains again, a couple days ago it became unbareable and I started getting morning sickness, I remembered when I took one a day vitamins I got morning sickness also, so I stopped taking the centrum 2 days ago, the cramps are already gone as is the morning sickness, so whatever the difference between the regular mens centrum and the over 50 triggered my ibs