For many years I have been suffering from IBS. It is not with C or D, just the urge to go to the bathroom three or four times a day. I have been taking Fiber Con ( or its equivalent) every day until a nutritionist told me to stay away from it. She suggested I should digest more soluble fibers found in fruits and vegetables. Wow! I started to feel better in a week. The lesson: find out if you need soluble or insoluble fiber.