Mag oxide can be used as an antacid, although I think they commonly use calcium carbonate instead. Check the threads here on various forms of magnesium, and you could choose something besides mag oxide if you want. The main issue with magnesium is that some people have digestive issues when consuming too much -- don't overdo it, or you'll spend all of your time in the bathroom. A resonable dose is fine for most people.
A lot of people here have used mag glycinate, which tends to cause a bit less in the way of symptoms than citrate. But it will vary by person. Regardless, look at iherb and Swanson's and I am sure you can find inexpensive brands of magnesium.
Edited by nameless, 26 July 2013 - 03:57 AM.