All four of our cats have had a day or so of Diarrhea the past week. They are all eating and drinking and playing normally. Look fine, clear eyes, running around and playing with toys. I wonder if it could be the drastic change in weather. It was about 60 one day then over 90 the next and lasted about a week and then about 50 at night and back into the high 80's again. I know it affects humans, I wonder if it must bother their systems too.