My 4 year old has had a stomach ache just before he poops for the past 5-6 days. It s been very runny and mostly brown in color with some green in the first few days. He s fine otherwise. Today he had a pudding-like poop and at the end was a yellowish piece of poop that was covered in a white fuzz coating. Any thoughts? Our Dr told us yesterday it was just a virus and not to worry, but the white has me nervous today.