@geranium1 Did you begin with the full dose ? I feared that problem as a CRC patient, so I started slowly, and in a month hope the full dose feels okay…also, they go better taken with food, and extra hydration helps.. some people especially sensitive to the magnesium in many of these combos— so they take separate supplement elements… sometimes reactions depend on what type of calcium or magnesium is used….good luck whatever you chose !