Usually yellow stool can sometimes be indicative of milk allergies or fat processing diffciculties in the colon; OR if it is more grayish and clay looking in color and consistancy- you might want to have your doc do liver function tests, it could be lack of billirubin which is processed by the liver. Since the side effects of this stupid monster in our cervix are so unknown, I would call the doctor ASAP and let him know- it could be affecting your liver function or the way your colon is processing fats.