We are all different in that magnesium can put some in the toilet with the smallest amount and other can handel it. THe Caltrate Brand in the purple and white bottle has 40 mg and for some this is too much. I do not seem to have a problem with it though. You can just get a calcium carbonate and vitamin D and if it list magnesiun in the chemical content list it is not in an amount that will cause a problem in most cases. You can get other brands with the same ingredients and I use the Sam's Club version call Member's Mark which is the same as Caltrate in the purple box with 40 MG of magnesium.Linda