This study shows that taking too much calcium, no magnesium or vitamin D3 can cause problems. By reading the title of the article it sounds like calcium itself is dangerous. You must read the whole study to see that the problem was adding 1000 mg of additional calcium daily and no magnesium or vitamin D3. The moral of the story is, too much of anything is no good, and taking anything the wrong way is not healthy. Click here to see the article and how it does not tell the whole story.