I'd always heard that taking iron could cause constipation, so imagine my surprise when the exact opposite happened. My mistake- if I had read the ingedients of Feosol, I would have known the manufacturer had included polydextrose, lactose and sorbitol. Why they are included, I have no idea- sorbitol is an artificial sweetener, a sweetener isn't needed in a pill you swallow, and sorbitol is known to cause diarrhea. Lactose will definitely cause it if you have lactose intolerance. Polydextrose causes “abdominal Bloating, cramping and excessive gas” according to Healthfully.com. Including all three seems just plain mean :( The miserable side effects were not worth continuing with Feosol