Part of the problem is that we are not getting it in our foods, the soil is so depleted we don't get nearly the nutrients are grandparents did. Yes, magnesium can have a laxative effect if you take too much... but why would you overdose on a magnesium pill. Have you ever noticed that some antacids have magnesium in them. Look at the label. That's why it's makes more sense to just take the supplement to cut the neutralize the acid. If I have said it once I will say it again. Those acid reducers are the problem. You need acid to digest your food. Without it we get more heartburn and more gas. It has worked wonders for me. Get the book I mentioned on Amazon.com. you'll see.