I started with the Caltrate in the purple and white box and never switched from that form and I was just interested to know which form most are using to help to control the diarrhea. (I use the Sam's Club version of the Caltrate in the purple and white box exactly the same ingredients).Pink and white has Calcium Carbonate and Vitamin D.Purple and white had Calcium Carbonate, Vitamin D, Magnesium, Zinc, Copper, Manganese, and Boron.Of course I am relunctant to switch because of the great results but then I was thinking if Magnesium causes diarrhea in most I maybe able to reduce the dose if I took the one without the magnesium which I know does not cause me a problem in the low dose that is in the Caltrate.With the Caltrate in the purple and white box I must take 3 a day which is fine because I need the calcium to help prevent bone loss but I was just wondering which one most of you use if you use the Caltrate Brand.Linda