I don't think my vitamins were the cause of my 2 year bout with Diarrhea but have noticed one thing. Since I stopped taking any in the a.m. and now taking a Probiotic things have changed dramatically. I knew that too much vitamin C could give you Diarrhea, so now after supper I take my multi...500 C..600 calcium and then about an hr. after supper take a Probiotic.
Hubby was taking some sort of a power booster drink and started getting Diarrhea. I told him it had a lot of vitamin C in it and only take it every other day...WALA..problem gone.
Hope this helps...JJ...