What does it mean when you have a gray stool? i take 325mg daily of ferrous sulfate (iron) so the stool is usually black. it has been gray for about a week.

Good : Good news! the only stool colors we get really concerned about are red (blood from colon), black (blood from small intestine or stomach), or white (liver is not working well). And in your case since you take iron, black stool would be expected and not worrisome. Colors such as brown, yellow, orange, green, gray, even blue (blue kool-aid or blueberries) or purple (beets) can all be normal and usually associated with diet. If you have a persistent change in your stool habits, you should contact your physician since this could be a sign of an underlying disorder, but a short period of strange stools that are not red, black or white is usually of no concern.