I guess too much of anything can cause nausea, but it doesn't sound like you're taking too much calcium, especially if it's keeping your diarrhea under control.
Yes, calcium supplements can actually ease the annoyance of heart palpitations. It's kind of a long explanation but it does seem to work somewhat for this purpose. Magnesium, on the other hand, can increase palpitations while it increases bowel movements. Interesting how these minerals work!
Co-moderator - IBS Forum