I've just recently started taking caltrate myself and I'm taking just one a day with dinner (it's the only real meal I eat). I've only been taking it for about a week and so far I haven't had any D attacks, but I've been really good about watching what I'm eatting. It depends on how bad your D is. If it's bad you may want to start with 1/2 pill 3x a day at meal times. I'm sure everyone can tell you different amounts they take.....you just have to find out the right amount for you by starting out with a smaller dose and work it up til you get it right. Good luck and I hope it works for you.