In cats, obstipation is described as the inability to defecate, a very painful and serious condition that demands prompt veterinary attention. The causes of this backup are not well-understood, but they result in intestines that become dilated and unable to push stools out of the body normally.

If your cat is straining or crying out while trying to defecate, or if you notice an absence of feces in the litter box, your pet has a potentially serious problem. Oddly, this blockage may initially appear as diarrhea because your cat's body, so irritated by the retained feces, may generate lots of watery fluid or mucus to try to cope. This discharge may seem like "ordinary" loose stools when passed.

Any changes in your cat's litter-box habits need to be investigated by your veterinarian, the sooner the better, and obstipation is no exception