Feline inappropriate elimination (Proceedings)


Feline housesoiling still represents the most common reason cat owners seek behavioral advice from their veterinarian. Inappropriate elimination can be seen in all ages and breeds of cats and often can be frustrating to resolve. The causes are multiple and sometimes complex.

Feline housesoiling still represents the most common reason cat owners seek behavioral advice from their veterinarian. Inappropriate elimination can be seen in all ages and breeds of cats and often can be frustrating to resolve. The causes are multiple and sometimes complex. Many litterbox problems can be prevented by establishing good litterbox habits when the cat is young and also by educating the owner on good litterbox management.

Kittens should be confined in small areas (cage, bathroom, bedroom, etc) while they are learning to find and use the litterbox. Close proximity to the box will encourage usage. If young kittens stray too far from the box, they may be unable to find the box or reach it quickly enough once the urge to eliminate occurs. Kittens gradually can be given more freedom as they grow and learn the layout of the house. Litterboxes for kittens should be large enough to allow the animal to maneuver inside the box, yet shallow enough for the kitten to easily jump inside. The owner may need to purchase subsequently larger boxes as the kitten grows.

Medical evaluation

Every elimination case should begin with a thorough medical evaluation. For inappropriate urination the minimum evaluation should include a complete physical exam and urinalysis. Similarly for inappropriate defecation, a complete physical exam and fecal are warranted. A large percentage of cats that I see with inappropriate defecation have elimination issues related to chronic or intermittent diarrhea of various etiologies. In many cases when this underlying disease is controlled, the fecal housesoiling resolves spontaneously.

Litterbox management

Size, location, litter choice and hygiene are important aspects of good litterbox management. Boxes must be large enough to allow the cat to comfortably maneuver inside. Commercial litterboxes often are too small for many cats. Sweater boxes make excellent alternatives for these cats; they are economical and can be purchased in a variety of sizes. The litterbox should be located in a relatively private area that is easily accessible to the cat.

Litter should be chosen to appeal to the cat, not the owner. Most cats prefer fine grain clumping litters. Deodorants and strongly scented litters should be avoided as many cats find these offensive. Any change in litter type should be done gradually over a span of one to two weeks.

Multiple litterboxes should be available in multicat households. In general, there should be one litterbox per cat plus at least one extra. The more cats that are in the household, the more extra boxes there should be in the home. These boxes should be distributed in multiple locations and not situated close together.

Litterboxes should be scooped a minimum of 1-2 times per day. Some extremely fastidious cats will only use a completely clean box. Litter needs to be completely changed on a regular basis, even if the owner is using a scoopable litter. Scoopable litters are usually changed every 2-4 weeks, whereas non-clumping litters should be changed at least twice per week. Litterboxes should also be cleaned on a regular basis; the frequency will depend on litter type and the number of cats using the box. Litterboxes should be washed with warm water and soap. Owners should avoid disinfectants. If residual odor is a problem, the owner can soak the box in an enzymatic odor neutralizer such as Outright® or Anti-Icky Poo.®

Inappropriate elimination

Inappropriate elimination can occur in any age, sex or breed of cat; however, Persians, Himalayans and related breeds appear predisposed to housesoiling problems. Inappropriate elimination may manifest as housesoiling (urine and/or feces), horizontal urine marking, and/or urine spraying. Fecal marking does occur but is much less common than urine marking.

All cases of inappropriate elimination should receive a thorough medical evaluation. Urinalysis and/or fecal examination should be done with every case. Additional diagnostics are often indicated. Practitioners should be particularly suspicious of medical issues in senior cats and when cats with previously good litter box habits abruptly begin housesoiling. Declawing surgery is a common trigger for inappropriate elimination in young cats. Interstitial cystitis is often associated with random and frequent inappropriate urination throughout the house, and the problem may appear cyclical.


A detailed history is critical for accurate diagnosis. Information should be acquired about the nature of the problem (e.g. urine, feces or both), current and past litterbox management, the animal's environment, and social issues. Many clients have made changes attempting to resolve the problem and this information is important as well.

It is helpful to have the client give a chronological account of the problem as this provides information on the onset, duration and progression of the inappropriate elimination. Clients should also be encouraged to draw diagrams of their house, indicating soiled areas, furniture, windows, doors, location of the litterboxes, location of food and water bowls, and the areas where the cats spend most of their time.

The critical step in the diagnostic process is to differentiate housesoiling (a toileting problem) from marking behavior. An inability to or lack of attempt to differentiate these problems (and thus get an accurate diagnosis) is one of the major reasons for treatment resistance. This distinction is also necessary to determine if pharmacological intervention is appropriate or not.

Differential classifications for housesoiling include inadequate housetraining, inadequate access to appropriate elimination areas, litter/box aversion, substrate preferences or aversions, and location preferences or aversions. Inadequate access may be due to physical, environmental, or behavioral constraints. For example, an elderly cat may have to climb stairs or over a gate to get to the litterbox, or the litterbox may be located near the washing machine of which the cat is afraid. Alternatively, in a multicat household, one cat may be preventing another cat from accessing the litterbox area.

Substrate preferences are common in cats and often arise as a secondary problem to another inciting cause (e.g. a bout of cystitis that drives the cat out of the litterbox). Cats generally prefer soft, absorbent surfaces and will frequently eliminate on bathmats, bedspreads, laundry, and carpet. Litterbox or substrate aversions are also common. Dirty litterboxes are a common cause of housesoiling. Medical issues that create discomfort when the cat eliminates also can trigger litterbox or substrate aversions. The cat may associate this discomfort with the litterbox and elect to try eliminating elsewhere. When cats eliminate directly outside the litterbox, it is almost always an indication that the cat has some issue with the box, the litter, or its cleanliness. Other clues include the cat trying to stand on the edge of the litterbox or showing reluctance to enter or remain inside the box. Cats may also be reluctant to actually scratch in the litter before or after eliminating.

Location preferences may be primary or secondary problems. The cat usually chooses one or two select areas in the house. Location aversions are typically related to environmental stimuli in close proximity to the box (e.g. appliances, a dog crate, doorways). The cat may eliminate indiscriminately in several other areas or choose one to two specific locations. These locations are often in low traffic areas in the house such as the dining room or a spare bedroom.

Marking behavior may be manifested by deposition of urine on horizontal surfaces or by spraying on vertical surfaces (and less commonly by deposition of feces). Triggering stimuli are associated with territorial, social and environmental (stress) issues. It is useful for owners to understand that some cats urine spray in response to strong odors such as dirty laundry. Urine marking is not always about territory or dominance; sometimes it's just a piece of information with no ulterior motive – "I was here and this is interesting." Some cats also urine spray or phantom spray associated with arousal such as when the owner returns home. Nevertheless, urine marking does frequently relate to a specific issue in the home. Urine marking is typically a reaction to social triggers (animals, humans, separation) or environmental triggers (olfactory, visual, new items in the house). It is often associated with variable levels of stress and anxiety, which is why these cases often benefit from adjunctive drug therapy. Accurate identification of the triggering stimuli is important for successful therapy. Information on social relationships is extremely important with cases of inappropriate urination and urine spraying, particularly in multi-cat households. By far, the majority of cases of urine spraying in multicat households are driven by social strife. Owners often have difficulty identifying covert aggression in cats. Owners should be questioned closely about the cats' body postures and reactions to each other under various contexts. Use diagrams of cat body language and/or have the owner videotape the cats to better delineate any potential problems.


Treatment focuses on preventing the animal's access to stimuli that trigger the inappropriate behavior while concurrently establishing more appropriate litterbox habits. The owner should prevent the cat from having access to previously soiled areas. In the case of surface preferences, the cat must be kept away from the preferred surface. In most cases, this means confining the cat in some fashion – in a bedroom, bathroom, or cat cage for example – depending on the distribution of the problem. Soiled areas should be thoroughly deodorized with an enzymatic odor neutralizer to reduce the cat's attraction to the area. The owner should be assisted in correcting any deficiencies in litterbox management.

Litterbox and substrate aversions are resolved by taking steps to make the box more attractive to the cat. The cat should be confined with 2-3 litterboxes, which are manipulated to provide the cat with a preference test. One box should be identical to the cat's regular box. The other two boxes are each changed in only one way. For example if the regular box is uncovered, one new box may be covered with the cat's regular litter while the other may be uncovered with a novel litter. The owner is instructed to keep a journal documenting the eliminations that occur in each box over the subsequent 5-7 days. Once a pattern of preference is noted, the preferred box is kept unchanged and one change is made to each of the other two boxes. This process is repeated until the owner has identified a litterbox arrangement that the cat consistently prefers over all others offered. Owners should be forewarned that they should cycle through several litters (at least six) and not stop after trying just one or two. Examples include: recycled newspaper, clumping wheat or corn litter, play sand, wood chips, regular clay litter, topsoil (very useful for cats making a transition from outdoors to indoors), crystals, pearl litters, and non-disposable diapers or carpet remnants (for cats with carpet surface preferences). Litter additive products such as Cat Attract® are sometimes helpful.

Environmental stresses can often be controlled with management and preemptive steps such as using Feliway for several days before owners travel or spraying the product on new items that will be brought into the house. New items in the house can also be confined in an area where the cat cannot go until the item has been in the house long enough to lose most of its novel odor.

In multicat homes, encouraging the cats to show behavioral separation can reduce social stress. All resources should be spread throughout the house. There should be multiple locations for food, water, litterboxes and favored resting areas widely distributed throughout the home. When severe social stresses are present (e.g. intra- or interspecies aggression), these must be addressed using a desensitization/counterconditioning program.

Drug therapy is helpful and often necessary when social or environmental stressors are involved. It offers almost no benefit for cats that have location, substrate, or litterbox issues and should not be used for these issues.

Psychopharmacological agents should not be used frivolously. Clear indications should be present and the practitioner should evaluate the benefits in relation to risk of drug interactions, complications for existing medical conditions, drug side effects, and the cost to the owner. Additionally, the practitioner should remember that all psychotropic medications are extralabel use in cats.

Historically, diazepam and progestins were used most commonly for treatment of urine marking and spraying. Progestins produce non-specific effects and can be associated with a wide range of serious side effects. For these reasons, these drugs are no longer recommended except as a last resort. Benzodiazepines act rapidly and are economical as well as effective; however, they should be used with caution in cats due to the risk of idiosyncratic hepatic necrosis. Due to the number of other pharmacological options now available, these two classes of drugs are usually not recommended as first lines of treatment.

Serotonin modulators represent the newest group of drugs available to assist in treatment of anxiety related elimination disorders. These fall into three broad categories: tricyclic antidepressants (amitriptyline, clomipramine), selective serotonin reuptake inhibitors (fluoxetine, paroxetine), and atypical antidepressants (buspirone).

Tricyclic antidepressants (TCA's) modulate levels of both serotonin and norepinephrine to varying degrees. They also have anti-histaminic and anticholinergic effects and these latter properties account for most of the side effects. Amitriptyline (1 mg/kg BID) is particularly effective due to its potential positive effects on neurogenic pain associated with interstitial cystitis. Its onset of action is slightly more rapid than that of clomipramine. Clomipramine is more selective for serotonin effects and has less antihistaminic properties than many other TCA's, so clients often see less sedation. Clomipramine is dosed at 0.5 mg/kg SID in cats.

Fluoxetine (Prozac) and paroxetine (Paxil) represent SSRI's commonly used for adjunctive therapy in elimination disorders. Fluoxetine is dosed at 0.5 –1.0 mg/kg and paroxetine at 0.25 – 1.0 mg/kg. I typically recommend starting at the lower dosages and evaluating the cat's response in 2-4 weeks. Buspirone is a partial serotonin agonist dosed at 1 mg/kg BID or 2.5-5mg per cat BID. This drug has demonstrated equal efficacy to diazepam for control of urine spraying. Both SSRI's and buspirone are relatively void of side effects, although some animals may demonstrate agitation or hallucinogenic-like behavior on buspirone. Unfortunately, to date, studies indicate a high relapse rate for urine spraying once drug therapy is withdrawn, particularly if owners are unwilling or unable to sufficiently alter the cat's environment to correct the trigger long term.

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