We have two cats, ages 13 and 17. One or both of them (we believe the older one) is leaving both urine and feces outside the litter box on an almost daily basis. We try to keep the litter clean and have no idea why he keeps on doing this. How can we retrain him? 

This is a fairly common problem in cat households. Cats will go outside the litter box for several reasons. Visit your veterinarian to make sure there are no underlying medical problems, such as kidney disease, diabetes, urinary tract infections or other issues. Often, when cats have to urinate very frequently, they will be unable to make it to the litter box. There are other issues such as constipation that can cause cats to have bowel movements outside of the box. Another common cause, especially in older cats, is arthritis — it can be difficult for arthritic cats to climb into a box with tall sides. 

If medical problems are ruled out, behavioral changes need to be considered. Cats may get frightened while in the litter box (loud noises, harassment from another pet) and this can deter them from using the box.

Cleaning the box daily, and making sure you have enough boxes in the house (usually the number of cats plus one) in enough locations (one on each floor) can help to solve some of these behavioral problems. A change to a different cat litter can sometimes be useful. If these management changes do not help, your veterinarian will be able to discuss other ways to modify behavior.

Dr. Laural Casler is a veterinarian at Eastern Animal Hospital, Baltimore. Send your questions to sun.unleashed@gmail.com.