My little cat Sir Didymus had an upset belly one day and was barfing and barfing and had a leaky bum. We brought him to the ER, they gave him some fluids and belly meds and send us home. The next day he was fine, except that his poor kitty bum was quite literally licked raw to the point of bleeding. A few days later, a random turd on the step. Weird, cleaned it up. Next day, a few random turds in the hall. Again, weird, cleaned it up. Next morning? Pile of turds on the floor in the living room. NOT COOL GUYS!! I figured it was Did cause he'd just been ill, and one day I caught him in the act. We have 3 cats and already had 4 litter boxes; 3 in the basement, one on the second floor. We ended up adding a FIFTH box in the first floor bathroom (it just barely fit) and used different litter in it, and the poops stopped. I don't know if he couldn't make it, or if he was associating the litter box with kitty bum pain, or the litter was irritating his already irritated bum, but he was happy with box #5. We left it upstairs for a while, then moved it to the basement (it was REALLY in an inconvenient location on the first floor) and he's not pooped on the floor since.