Calcium carbonate is the active ingredient in Tums. While it may reduce heartburn if chewed, very little, if any will get into your blood stream. You might try taking the pills with orange juice so some will dissolve and turn into the very absorbable calcium citrate.

You can get enough of both magnesium and calcium in your diet, and supplement minimally because of your special needs as somebody with PN. Here's a pretty good discussion on the topic: http://www.hsph.harvard.edu/nutritio...e/calcium.html . They mention Tums, but neglect to mention that it's not absorbed very well.

There's a lot of flim-flam out there in the supplement world, with useless products being highly touted by the sales people. With calcium, the least useful types are calcium carbonate and it's "natural" clones, oyster shells and coral (both are the same as limestone). Dolamite is still sold. Besides not being absorbable, it is laced with toxic heavy metals.

There's no magic pill or simple answers. Every PN related health topic I've looked at over the years gets complex and conflicted the closer you look at it. I think a generally healthy and balanced approach with good diet, enough exercise, some supplements (I take far more than I probably need), a positive attitude, and avoiding toxic chemicals and toxic people will eventual relieve your pain and help heal your PN.