Denis,
Sensitivity to something in your multivitamin doesn’t seem outside the realm of possibility. Most of these nutrients can be obtained in ways other than through supplements. If you click on the link to more information at the end of each nutrient’s section, you’ll be taken to a page that provides alternative ways for obtaining the nutrients.
Good luck!

Dylan,
I don’t recall my exact thought process at the time, but in retrospect, I don’t think there’s any problem with including iron and it might slightly benefit some people. One exception would be for people with hemachromatosis, but they already know to avoid supplements with iron.

Noam,
Multivitamins don’t contain enough calcium to make them a good source. The volume of calcium would be too much to fit in one tablet with the rest of the nutrients. So you need to get calcium from a different source as I describe above. Most multis have vitamin A, including the ones I recommend below.

Pepo,
I emailed you using the email you submitted with your comment. I had follow-up questions and didn’t want to discuss it through the website. See if you got the email.

The amount of calcium in a multivitamin isn’t anything to worry about with regard to iron. A multivitamin shouldn’t be relied on for iron. The most important thing for increasing iron absorption is to add vitamin C (mentioned above in this article) and avoid tea and coffee at meals. If you have diagnosed iron deficiency then you should probably be taking an iron supplement under the guidance of a physician.