Cats are fastidious so if your cat resists using the litter box you need to make some changes. The most common reason your cat may stop using the litter box is that it is wet and stinky. If the box is too gross, your cat will find someplace less appropriate to do her business. Your cat may also stop using the litter box because she is stressed. Your cat can be stressed by the presence of new household members including other pets. Houseguests and construction work in and around your home may frighten your cat into staying away from the litter box. You may need to set up a litter box closer to wear your cat hides out as she works through these issues. However, avoiding the litter box may also indicate that your cat is not feeling well and needs medical attention. Learn more from your Orleans County, NY veterinary clinic.