MaNdA22, it's probably the iron in the supplement that's doing that -- I get the same thing with any supplements with iron.
* * *
I take:
-MultiPlus vitamins & minerals (every 3rd day, as it irritates my medical condition if I have it too often)
-calcium + magnesium
-Vitamin D (medical reasons)
-evening primrose oil (around TOM)
-fibre supplements
I have a medical condition that restricts my diet quite a bit, so I have to be careful to get my nutrients!