Welcome to PT!!! Sorry to hear of your problem with your cat. First, is she fixed? Is the box CLEAN(cats are VERY fussy about the condition of their toilet, just as we are)? Has your cat been to the vet to make sure she does not have an infection? Is the litter scented? Are there other cats in the house that might have scared her while she was using the box? IS the box located out of the way where she might have a problem getting to it in time(esp if she is older)? I am sure others will post, too, with other ideas for you to consider!! Good Luck!!!