Susan Little, DVM

Received: November 1996

The most common behavioural complaint about cats presented to animal behaviour consultants in North America is house-soiling. The typical presentation is that of a cat that both uses its litterbox and eliminates outside of it. It is also typical for the cat to deposit only urine or stool outside the box, but not usually both.

It is critically important to discriminate between medical and non-medical causes of a behaviour problem. The common occurrence of feline lower urinary tract disease (FLUTD – formerly called FUS) makes this especially important for house-soiling problems in cats. This holds true whether the problem is soiling with urine and/or stools, or if it involves spraying or marking behaviours. A good history of the problem is second in importance only to the tests required to rule-out medical problems for both diagnosis and treatment. It is essential to establish an accurate diagnosis for each case.

Remember that a problem behaviour is not necessarily an abnormal one – most problem behaviours are actually normal ones which are exhibited in an inappropriate manner.

When your veterinary surgeon is taking a history of a housesoiling problem be prepared to give information such as:

  • a detailed description of the problem, its duration, progression and severity
  • a description of any associated events
  • a description of any corrections already attempted
  • a description of the environment: ie. number of animals, number of litterboxes, locations of boxes, interactions between animals, etc.
  • medical history (ie any history of intestinal problems or FLUTD)

There are 3 basic categories of housesoiling problems:

  1. normal elimination at an inappropriate site (most common type)
  2. marking behaviour (spraying). It is important to distinguish between urinating outside the box and spraying – this is done by a description of the cat’s body posture and location of the urine voiding.
  3. medical disease
  • or a combination of any of the above

After taking a complete history of the problem, your veterinarian will want to run some medical tests. A urinalysis is always indicated when house-soiling involves urine, and is usually necessary if stools are involved as well. It is not unusual for a cat to have a medical problem when the behaviour history is suggestive of only behavioural factors. Other tests may involve blood samples to determine if another medical problem, such as kidney disease, is contributing to the housesoiling.

A diagnosis is reached by applying criteria to show which of the potential contributing factors (both medical and psychological) are involved. A working diagnosis has the advantage of suggesting the factors which must be modified in the treatment plan. A treatment plan is then formulated. The plan should be designed to: entice the cat back to the litterbox using any changes (sometimes extraordinary) necessary, and modify the inappropriate site to make it unattractive or inaccessible.

It helps to understand that elimination in cats is actually a sequence of individual behaviours, and a problem can develop at any of the steps involved. In nature, cats have an infinite variety of sites and substrates for elimination, but in a home setting, they are expected to use a restricted number of sites (often only one) and a restricted type of substrate (again, often only one).

The elimination sequence:

  1. search/approach location – involves visceral sensation
  2. dig – involves tactile sensation (very important)
  3. eliminate – involves visceral sensation
  4. sweep/cover movement – involves tactile sensation

The contributing factors to housesoiling:

  1. Litter aversion: a common cause of house-soiling. A cat selects a site initially based upon the tactile sensation created when it scratches at the surface.
    A cat may dislike litter because of:

    • – inadequate cleaning (some cats are extremely fastidious, and this can set off a litter aversion)
    • – learned aversive association with the litter due to: pain (ie FLUTD), diarrhea, fear (owner catches it in litter to give it medication, or another cat in the house always traps it there to attack it), odour (either from inadequate cleaning, or from deodorizers or cleansers used by the owner)
    • – an unlearned spontaneous individual aversion – just doesn’t like the tactile sensation of the litter type
    • – a plastic type litterbox liner is being used, so the cat catches its claws on it when it tries to dig
    • – the litter type itself may be OK, but there may be too little in the box or too much
    • – and just to complicate things, some cats dislike the litter if you keep it too clean

    Signs of litter aversion:

    • – cat avoids litter completely
    • – cat uses litter, but scratches at the sides of the box, on the floor, or other objects nearby instead of in the litter
    • – cat uses litter, but shakes paws a lot during and after using it
    • – cat does not dig in litter
    • – cat straddles the box, putting feet up on edge of box to avoid touching the litter
    • – cat uses litter, then bolts out of box quickly
    • – cat meows at or talks to litterbox
    • – cat starts urinating in box in normal squatting position, but ends up standing and spraying urine

    There are several steps that can be taken to correct the problem, but first ensure that the litter is clean. Then be sure you are not using a deodorized litter – some cats find these scents very distasteful and review your cleansing procedure. A product with an odour used in the cleaning process may cause a lingering smell – change your routine, if not in a cattery, try using only very very hot water and no cleanser. If you are using a litterbox liner, stop. Try different types of litter: you may have to try quite a few systematically (for 7 to 10 days each) to find the right one (you may have to try a wide variety of different materials). Cats can spontaneously decide that a litter they have happily been using for years is no longer attractive to them. If you want to make changes to the litterbox filler or location, always make these changes gradually. For instance, if you decide for whatever reason you want to use a new litter, first use an additional box with the new litter and gradually take away the old litter once the cat is happily using the new one. For changing the location of litterboxes, the same applies – add a new litterbox in the new location, and gradually move the old box day by day to the new location (means you will have a litterbox in unwanted places but it’s only temporary).Finally, remember that some cats prefer two locations for elimination: one for urine and one for stool. Providing enough litterboxes for this may be all that’s needed.

  2. Surface preference: a cat may find another surface in the house it prefers to the litter provided in the litterbox. This is very common. Even in cases in which some other factor was the initial cause, a cat can develop a new surface preference. The most common preferred surface is some type of fabric, with carpeting being number one. Sometimes these surface preferences can develop accidentally, ie. the cat accidentally scratched at the bathmat hanging next to the litterbox and develops an association between elimination and the fabric. Cats can also have a primary preference for one type of surface over another – ie they just like carpet better. A nice study involving an experimental trial of different litters for cats (Dr. P. Borchelt, Vet Clin of N.A., 21(2), 1991) showed conclusively that cats prefer finely-grained textures. Therefore, the most preferred litters are the sandy, clumping types. Second most preferred would be actual playbox sand. Third would be the finer traditional clay litters. Last would be products such as wood shavings and recycled newspaper.There are some cats who actually prefer a smooth surface – they will be the ones eliminating on a floor surface, in the sink, bathtub, etc. They may respond to an empty litter box, or one with a bit of tornup newspaper. You can then try adding litter very slowly and in small amounts to the box. Carpeting presents a particular problem as it is almost impossible to clean. Urine odour is very pervasive and usually soaks into not only the carpet, but the underlay, and even the flooring underneath. For lightly soiled areas, clean with a odour eliminator such as KOE or Outright, or get a professional carpet cleaner in (most home steam cleaners won’t help). In many cases, the carpeting must be ripped out or the area re-floored in another material. It may be necessary to place a piece of scrap carpet in the litterbox itself to get the cat back to the box or to build a small platform surrounding the litter that is carpeted, so the cat can perch on the platform.It may be necessary to block access to areas previously soiled (ie. keep bedroom door closed, cover the soil in plant pots with a fitted mesh or add lots of pebbles, move a large object on top of a soiled area). Areas can be made undesirable by many tactics: covering the area with tinfoil (don’t use plastic, many cats love to urinate on it), using moth ball flakes (as long as there is no danger of a child or dog ingesting it and you only need a small amount). For cats who get up on countertops and urinate in things, place a strip of double- sided sticky tape on the edge of the counter so the cat’s feet will touch it when it lands there – most dislike the sticky sensation. In some cases, you may need to resort to using a motion detector that emits a noise when the cat disturbs the area, this works very well; and most cats will learn to avoid the area after only 1 or 2 tries. However, be sure you want the cat to totally avoid the area (ie its not your favourite place to sit and cuddle), and if you have neighbours, you better warn them of the noise as it may scare more than the cat. For bathtubs and sinks, leave 1 inch of water in them. For only one or two favouritely soiled areas, try feeding the cat at that spot. In North America, there are companies who sell indoor versions of the “invisible fencing” systems used outdoors that could be used to keep a cat from certain indoor areas.There are many other creative ways to make a spot aversive to your cat, but they must be used in conjunction with tactics to get him back to the litterbox, for if you train him to avoid one area he will go to another instead. In some cases, it may help to isolate the cat in a small area (typically bathrooms are used) with the litterbox, a sleeping spot, toys, food etc to enforce re-training. Make sure the food is not too close to the litter. This process may have to be carried out for 2 weeks or more. The cat can be allowed out of isolation only when the owner is around to carry it at first, then gradually for little play sessions, or cuddle sessions, gradually increasing in time providing no relapse to house-soiling occurs (if it does, you went too fast, start all over again).
  3. Location/Litterpan aversion: the location or the box itself can become associated with aversive events for the same reasons that the litter itself can (ie pain, fear, odour, etc.). Most cats prefer an easily accessible spot, but one with some privacy. So strike a balance between getting it out of the way for your own sake, and making it private but not too distant for the cat’s sake. Some cats prefer open boxes, some prefer the privacy of closed boxes, most like large boxes, a few like small ones.Cats will learn a preference in which elimination becomes associated with a specific location(s). This type of preference can develop very quickly if a cat first chooses to go out of the litterbox for any other reason. It is to be strongly suspected if a cat repeatedly goes back to one area, or one room. Some of these location preferences can become ridiculous, so don’t be surprised by anything (the most outrageous I’ve heard is a location preference for the middle of the dining room table). To help treat this type of problem, you may actually have to provide a litterbox in the cat’s preferred spot to get the cat using the box again, and then slowly move the box back to another location. Cats will usually dislike having to eliminate where they must eat, so don’t put the food bowl and the litterbox side by side.Anxiety-related causes: you must always consider the possibility that stress or anxiety is contributing to the house-soiling (still, this is not as frequent a cause of house-soiling as most people think).
    Types of stress:

    • separation anxiety: previously recognized only in dogs, now believed to occur in cats. Usually occurs when there has been a prolonged absence of an owner, ie over 8 hrs. The house-soiling will occur 8-12 hours after the owner’s departure, which is totally opposite to dogs, where the behaviour occurs right after departure. The behaviour may involve diarrhea and destructive events in addition to house-soiling. It can be treated similarly to the way dogs are treated (ie training through graduated departures – requires a lot of patience and time) and with some medications.
    • fear: cats that are naturally shy or fearful may not want to *come out into the open* to go to the litterbox. In some cases, there is an identifiable fearful stimulus, ie a certain person, cat, dog, object, sound that can be modified or removed. Desensitization and counterconditioning methods can also be used. You may have to provide a litterbox for that cat in some *safe* location.
    • overcrowding: there is a large variation in individual tolerances for overcrowding. Where some cats may be happy with 20 other cats in the house, others will dislike even 1 other cat, or even one other animal of any kind. Cats do not naturally live in social groups all the time, they spend much of their lives in solitary circumstances and get together for breeding or they may raise kittens communally, or if they are forced to by a limited food supply. Many cats may view all living beings (including people) in the home as part of the social group, and adding to the group in any way can upset them. You can decrease the number of cats/animals, you can increase the amount of vertical space available by adding cat trees, or even clearing bookshelves to allow cats to perch there (be creative). You can separate the cats/animals into smaller colonies within the home either on a permanent basis, or for a few weeks to resolve the problem and then try re-introducing.

In summary, make the simplest changes first, make all changes gradually, be prepared to address multiple factors, and be prepared to modify your treatment plan.

The prognosis is variable, and it partly depends on getting an accurate diagnosis. The longer the problem has been going on and the more severe the problem and the more animals in the home, the graver the prognosis.

For new kitten owners there are steps to take from the start to try to avoid housesoiling problems:

  • make the litterbox location easily accessible, but in a low traffic area
  • try to provide 1 litterbox per cat (or for those cats that prefer 2 locations, two boxes for the one cat)
  • use finely-grained litter types
  • do not put food and water beside the litterbox
  • scoop the box at least daily, change traditional litters at least once weekly and scoopable litters every 6-8 wks
  • avoid frightening the cat in the litterpan, or trapping and catching it there
  • **never, ever, ever punish a cat for house-soiling
  • **make any changes to the litterbox filler or location gradually
  • ** call the vet quickly if any housesoiling occurs

Biographical Profile of Susan Little, DVM

  • breeder of first Burmese cats, then Egyptian Maus
  • graduated in 1988 from the Ontario Veterinary College, Guelph, Ontario
  • in feline-only practice the last 6 yrs
  • many articles on feline health care published in breeder-oriented newsletters and journals
  • working on American Board of Vet Practitioners Feline Specialty certification
  • part-owner of a 2-clinic feline specialty practice in Ottawa, Ontario, Canada
  • husband, Edward graduated from the U. of Minnesota and has a veterinary internal medicine consultation practice in Ottawa
  • currently have 5 cats, 2 dogs, 1 pet rat named Elliott, and a 5 yr old daughter