You may want to ask your vet to check her back and back legs to rule out any spinal/joint issues that would prevent her from lifting herself into the box. A friend of mine uses a Rubbermaid "underbed" box that has very low sides for a cat of hers who is disabled. If she'll use it, you may also want to try a covered box which we always recommend to people whose cats tend to "hang over". In addition, make sure the area around the box is scrubbed with something like Nature's Miracle or Simple Solution which are enzymatic cleaners and remove the urine scent as well as the urine itself. Make sure the box is in a quiet, low-traffic area since cats feel they are at their most vulnerable when they are in their box. She may be perching on the edge to afford her a quick escape if she is being bothered by another animal or traffic in the area when she's using her box.

Izadore (Izzie) answered on 1/26/09. Helpful? / 1