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Feline Housesoiling Problems 
Part I:  Inappropriate Urination and Defecation

Article (c) and reproduced by kind permission of Dr. Barbara Sherman Simpson, MS, PhD, DVM
Animal Behavior Service of the Veterinary Teaching Hospital, North Carolina State University College of Veterinary Medicine,


Feline housesoiling problems are the most common behaviour complaints made by cat owners to primary veterinarians. In addition, elimination problems involve 33% to 59% of referred feline behaviour problems.1-4 If not resolved, housesoiling problems can lead to rehoming, relegation outside the home, abandonment, or euthanasia of the offending cat (Figure 1).5 These behaviour problems impact feline-human relationships, including the owner-pet bond, and can lead to the loss of the cat as a veterinary patient. The welfare of the pet as well as economic incentives should prompt veterinarians to develop expertise in the diagnosis and treatment of such behaviour problems.

Feline housesoiling problems can be divided into those relating to elimination outside the litterbox (discussed in Part I), including inappropriate urination. and defecation, and those related to marking behaviour, which can involve either urine or faeces (discussed in Part II). In all cases, it is imperative that medical differential diagnoses be eliminated before proceeding to behaviour therapy.4

Even when a medical diagnosis is made, behaviour therapy may be needed concomitant with medical treatment because behaviour problems can arise as a result of negative conditioning. For example, a cat experiencing urethritis may associate pain with the litterbox and seek alternate sites for urination. A behaviour .modification program may be required to re-establish satisfactory litterbox use.


Urine housesoiling problems include inappropriate urination and urine marking. Although both involve urine, the functions of each of these activities differ. Inappropriate urination, discussed here, involves elimination of urine outside the litterbox at locations. unacceptable to the owner. Urine marking (discussed in Part II) involves the use of urine in the act of olfactory communication, which may occur independent of the act of urination. Fecal housesoiling problems include inappropriate defecation, which may accompany inappropriate urination, and faecal marking, called middening (discussed in Part II).

Inappropriate Urination

Inappropriate urination occurs on horizontal surfaces outside of the litterbox and may be exhibited by individuals of any age, breed, or j sex. In cases of simple inappropriate urination, cats squat to urinate outside the litterbox. Often the location is in the vicinity of the litterbox or other locations in the house. Remote, private sites, such as behind a couch, may be favoured. There may be a specific substrate preference,6-7 such as topsoil surrounding houseplants, shag carpet, or small area rugs. A spontaneous preference for a novel or nonabsorbent substrate, such as a porcelain sink, may be associated with a lower urinary tract problem. Cats that urinate on the owner's bed or on clothing of specific individuals are exhibiting marking behaviour.2,8 This problem is discussed in Part II.

When medical causes have been eliminated, the behaviour history should include information on environmental factors that may be contributing to the problem. One common behavioural cause of inappropriate urination is dissatisfaction with some quality of litterbox, including insufficient cleaning.

Another important environmental factor is the relationship with other cats in the household: For example, another resident cat may provide olfactory cues litterbox that deter the problem cat from the site or playfully pounce on the problem cat as it exits a covered litterbox, forcing it to seek "private" elimination site where. Evaluating features of the litterbox and social environment requires a systematic process of "asking the cat" what it prefers. This approach involves providing boxes with different litter types in different location counting the number of eliminations per box per day.

In general, inappropriate urination can be effective treated by environmental control. Cats with a h of intermittent hematuria and waxing and waning may benefit from presumptive treatment for inter cystitis. Such cats may benefit from the use of the cyclic antidepressant amitripryline (discussed in II), which has been used for the treatment of inter cystitis in women; it has also been shown to be effective for management of feline interstitial cystitis.9

Inappropriate Defecation

There are numerous behavioural diagnoses for inappropriate defecation, including dissatisfaction with such qualities of the litterbox as location, type, or cleanliness. In these cases, inappropriate

defecation may accompany inappropriate urination.8 Observation of the cat may be suggestive. Although there are individual differences, the normal behaviour sequence for defecation involves choosing a site with loose substrate (such as a litterbox), digging a shallow depression, defecating at the site, and then covering the faeces with raking movements. The latter behaviour is stimulated by the odour of faeces and may be attempted when defecation occurs on the floor. 10

Cats that deviate from the normal behaviour sequence and straddle the litterbox, tiptoe into it, shake their paws after touching the litter, or exit the box immediately without covering the faeces are indicating an aversion to the litter.6 Some cats will not defecate in litterboxes that are cleaned infrequently. Other fastidious cats prefer to urinate in one litterbox and defecate in an adjacent clean box.

Social interference is a common cause of inappropriate defecation. Another cat may interfere with the completion of the problem cat's preferred defecation routine. A child or coprophagic dog in the household may follow the cat to the litterbox and disturb litterbox use. Surreptitious observation of the cat near the litterbox may provide important information about features that influence the cat's decision not to use it.


Elimination behaviour problems may be secondary to medical disorders. Thus a medical evaluation is indicated for all cases of feline housesoiling.

Urine Elimination Problems

All cats with elimination disorders should be physically examined with particular attention to palpation of the kidneys and urinary bladder. A neurologic examination should be performed. The general history should explore changes in eating, drinking, or activity patterns that may suggest a medical cause affecting litterbox use. For example, a cat with polyuria due to diabetes may find the litterbox unacceptably wet and may seek alternate locations for elimination. The owner's presenting complaint may be that the cat is eliminating outside the litterbox.

Appropriate screening tests should be performed. For urine-related problems, a urinalysis (including specific gravity and sediment analysis) is the minimum data base. The collection method should be by cystocentesis except in cases in which cystitis is suspected. In such cases, a voided sample should be obtained (if possible) to avoid further trauma to the bladder.11 Cystocentesis can result in inadvertent hematuria, which can be differentiated from cystitis by the absence of other signs of inflammation in the urine.12 Serial samples should be collected from any cat in which the behaviour symptoms wax and wane.

A complete blood count with differential and serum biochemistry should be performed as a screen on any cat with suspicious findings on physical examination and prior to the use of extra label medications.4 These values will be within normal limits if the inappropriate urination is strictly a behaviour problem. If the behaviour problem is secondary to a medical problem, there may be detectable abnormalities such as uremia, glycosemia, or hypercalcemia. Further diagnostics, such as plain or contrast radiography or ultrasonography, may be needed.

Inappropriate urination may be associated with a number of medical conditions, particularly those associated with hematuria, polyuria/polydipsia, dysuria, or pollakiuria. Older cats may suffer from arthritis or senility, which can limit their ability to 'locate and climb into a litterbox.8 Neurologic abnormalities may be implicated. Cats with refractory inappropriate urination should be tested for the presence of hyperthyroidism, feline leukemia, and feline immunodeficiency virus. The most common medical abnormalities associated with feline inappropriate urination are listed in Table I below.

Table I
Medical Causes for Inappropriate Urination in Cats

Type of Disorder




Traumatic Cystocentesis


Feline leukemia
Immunodeficiency Virus
Feline Infectious Peritonitis

Inflammatory disorders

Feline lower urinary tract disease
Feline interstitial cystitis


Diabetes mellitus


Intracranial cuterebral migrations
Feline dysautonomia
Seizure disorders

In a retrospective study comparing cats that exhibited inappropriate urination with controls, problem cats were significantly more likely to have had a history of lower urinary tract disorders (LUTDs).13 A survey at a large teaching hospital found that 37% of cases referred to the behaviour service for inappropriate urination had a history of feline LUTD.4 Feline LUTDs such as metabolic disorders (uroliths), congenital abnormalities, neurogenic disorders, and inflammatory and neoplastic processes should be investigated as potential underlying causes of inappropriate urination.14

Nonobstructive idiopathic interstitial cystitis is an LUTD characterized by inflammatory changes in the urinary bladder that may be accompanied by behaviour changes in litterbox use.15 Because the disease waxes and wanes, it may be in remission-and the urinalysis may be within normal limits-by the time the owner seeks treatment for the secondary elimination problem. Interstitial cystitis should

be considered in any cat with a history of hematuria and intermittent inappropriate urination.

Urine. marking is not usually associated with a medical condition; however, behaviourists have anecdotally noted an increase in spraying concomitant with inappropriate urination in some cases of LUTD,16 possibly due to agitation associated with pain. Therefore medical evaluation should be standard for any cat in which urine marking is associated with inappropriate (i.e., squat) urination or with medical abnormalities (e.g., hematuria).

Fecal Elimination Problems

In cases of fecal housesoiling, a fecal examination should be performed to rule out constipation, diarrhea, and internal parasites. Discomfort associated with constipation in the litterbox may cause the cat to continue to seek alternate sites not associated with pain. Enteritis or colitis may cause changes in elimination habits. Urgency associated with loose stool may make the litterbox too far away. Additional tests may be suggested by the history, physical examination, or fecal tests, particularly if concurrent illness is suspected.


At first inquiry, the client should be asked to keep a daily record of the number of eliminations in each litterbox and the number of eliminations outside the litterbox with the location noted (see Behaviour Diary below).

Behaviour Diary
Sample of a behaviour diary. Keeping such a diary reminds owners to clean the litterboxes daily, monitor the home for "accidents," and quantify the frequency of the problem. A simple form should be devised and given to owners to promote compliance.


Litterbox 1

Litterbox 2

Other Sites

1/21 Restricted during day







Living room




Living room
Laundry room

This information is used to quantify the frequency and location of the problem at the start of treatment. The process encourages owners to clean each litterbox daily and to monitor for new housesoiling incidents. After treatment is initiated, owners should continue to keep detailed records of all eliminations and their locations to evaluate the success of treatment.

As part of the behaviour history, the client should be asked to make a map of the interior of the home, with sites of elimination and litterboxes marked so that patterns can be visually identified (Figure 2). An electric probe to detect wetness in the carpet pad, available from professional carpet cleaners, may be needed to identify some urination sites.17

Solving an elimination behaviour problem often requires a search for information in the history that suggests the underlying cause. This investigation is facilitated by questions designed to provide "clues" that can lead to a specific diagnosis and treatment (Table II).

Table II
Historical Questions Regarding Feline Housesoiling



Which animal is eliminating? In single-cat households, there is no ambiguity. It may be difficult in multiple-cat households to determine with certainty which cat is responsible for inappropriate elimination. Often, one cat has been identified by the owner but more than one cat may be housesoiling. The offending cat(s) may be identified by serially isolating each cat and noting any change in the housesoiling pattern either visually or by the use of fluorescein dye (see text).
What is being eliminated? Determine whether urine, feces, or both are being eliminated inappropriately. " Dissatisfaction with the litterbox is strongly implicated when both are being deposited outside the litterbox.
If the elimination product is urine, is it deposited on vertical or horizontal surfaces? Vertical surfaces indicate urine spraying. Horizontal surfaces usually indicate inappropriate urination.
Where in the home does

housesoiling occur?

The use of a map with sites indicated by the owner is helpful and may indicate a location preference or influential social factors between cats (see Figure 2). An acute shift from one substrate, such as litter, to an unusual substrate, such as a porcelain sink, suggests a lower urinary tract disorder.
How often does elimination occur? Baseline frequency is necessary to determine the extent of the problem and to monitor improvement.
When does the problem occur? Daily or weekly temporal patterns of inappropriate urination may suggest a specific environmental trigger.
How long has the problem been going on? Acute onset in a cat that has previously reliably used the litterbox suggests a medical problem or a social cause. Duration of the problem affects prognosis. Chronic (months to years) problems have a guarded prognosis for complete resolution.
Were there any environmental changes associated with the onset

of the problem?

Changes in elimination habits can occur with environmental change, such as a move to a new house.
What measures have been taken to correct the problem? Learning what techniques have already been attempted can help guide the treatment plan.
Describe the litterbox

(location, size, box type, litter type, how often cleaned).

Dissatisfaction with the litterbox is a common cause of inappropriate elimination, particularly when both urine and faeces are involved (see Table IV).

Several methods may be used to positively identity which cat (or cats) is exhibiting inappropriate elimination in a multiple-cat household. Observing that inappropriate elimination occurs shortly after one cat's access to the litterbox is deterred by another cat is suggestive. Serial isolation restricts the spatial utilization -of each cat sequentially and monitors housesoiling. Each cat is isolated one at a time in a small room, and the "culprit" is identified by process of elimination. However, such a protocol may sufficiently alter the social milieu such that inappropriate elimination may not occur.

Fluorescein dye (0.3 ml subcutaneously, 0.5 ml orally, or six fluorescein strips in gel capsules orally) may be administered to one cat; any urine that is found outside the litterbox during the next 24 hours can be checked for fluorescence using a Wood's light.18 If such urine does not fluoresce, Fluorescein should be administered to each cat until the one responsible is found. A positive test does not eliminate the possibility that more than one cat engages in urine marking at other times. If fluorescein is administered but no urine is found outside the box (a common finding when the frequency of the problem is low), the test must be considered a diagnostic failure and should be repeated. Prior to administration of fluorescein, the owner should evaluate a "fluorescent-negative" urine mark with the Wood's light so that he or she can distinguish it from one that is "fluorescent positive."

Figure 2Figure 2 -Sample of a house plan submitted by the owner at the time of the initial visit. Litterboxes are marked with circled numbers. Feeding (F), play (P), and urination (U) sites are also noted. In this case, the problem was an older cat whose inappropriate urination began when a young, playful cat was added to the household. The older cat retreated to the master bedroom (presumably to avoid the young cat) and began to urinate outside the litterbox there. Access was to a covered litterbox in the master bathroom that was cleaned daily. When a second, uncovered litterbox was added in the master bathroom, the cat began to use that, and the elimination problem resolved. The covered litterbox was eventually removed.


Appropriate treatment is initially determined by the presence, if any, of a medical cause associated with the behaviour problem. Once any medical problems have been appropriately addressed and a behaviour problem has been identified, treatment may consist of one or more of the following: surgery, environmental changes, behaviour modification, and pharmacotherapy. A medical evaluation is always warranted prior to the use of medication. Treatment failure in a multiple-cat household should prompt reassessment. More than one cat may be housesoiling. Refractory cases or those in which the affected cat exhibits signs of anxiety or arousal may benefit from antianxiety medication (discussed in Part II).

Inappropriate Urination

The goal of treatment of inappropriate urination is to enhance the appeal and accessibility of the litterbox and to decrease the availability and appeal of alternate sites.8 Details of the behaviour history may suggest a treatment plan based on location or substrate preference. Cats that approach the litterbox and eliminate in its vicinity are attracted to the loose substrate but are dissatisfied with some other component of its quality or location." Methods of improving litterbox use are presented in Table III below.

Table III
Recommendations for the Treatment of Inappropriate Urination and Defecation in Cats 5-21

Treatment Modality

Specific Suggestions

Environmental control  
Litterbox Scoop out the litterbox daily. Clean it thoroughly once a week. Do not use scented cleaners or deodorants in or near the litterbox.

Provide at least one litterbox per cat and distribute them in more than one location. Be sure litterbox is not located in a high-traffic or high-noise area. Move food bowls away from the litterbox. If the litterbox is a covered type, provide an additional large, uncovered litterbox without a fitted rim to determine the cat's preference. Offer unscented, fine-grained, clumping-type litter in the alternate box.19 Do not use a liner in the alternate box because the odour of the plastic may be objectionable to some cats.8

elimination sites
Place an alternate litterbox over sites of "accidents." Once the box is being used regularly, it can be moved several inches per day to a site more acceptable to the owner. Use deterrents at the site of inappropriate elimination. These can be an unacceptable substrate such as aluminium foil or plastic sheeting or odour deterrents such as citrus spray. Pine cones may be placed at the base of houseplants to physically deter elimination there.
General management For longstanding problems and to reduce the owner's distress regarding damage to carpets and floors, it may be necessary to confine the offending cat in a small room (e.g., a bedroom) remote from sites of housesoiling. A litterbox, food, and other necessities should be provided. When regular litterbox use has been achieved or when the cat is well supervised, it can be let out of the room for increasing periods. Other management techniques should also be practiced. Clean all inappropriate sites with an enzymatic cleaner. Use a citrus deodorant spray or double-sided tape to discourage the cat from visiting problem areas.

Use an electronic sound alarm or electronic mat to deter a cat from an area where eliminations occur.

Behaviour modification  
Positive reinforcement Behaviour modification techniques include rewarding the cat with a favored treat for appropriate use of the litterbox.22
Punishment To be humane and effective, punishment must be of appropriate intensity and must follow within I second of the offensive behaviour. Because the latter is rarely possible, punishment is rarely effective. Corporal punishment or rubbing the cat's nose in the elimination product is not appropriate or effective. Punishment associated with sounds or movements by the owner (as reaching for a spray bottle) will condition the cat to avoid the owner. Counter conditioning may be used by feeding or playing with the cat at inappropriate elimination sites.
Pharmacotherapy Drugs are not usually indicated for inappropriate urination. Instead, an environmental and behaviour management plan should be implemented. Drugs should be considered for refractory or complicated cases of inappropriate urination (see Part lI).
Owner compliance Owners should maintain a record of the number of urinations and defecations inside and outside (with location) each litterbox each day so that progress can be documented.

The owner should monitor the house carefully for sites of inappropriate elimination so that the frequency can be noted and the site can be cleaned properly. Owners assume that the cat returns to the same site because of urine odour cues. Although this has not been scientifically demonstrated, prompt identification and cleaning of the site reduce the likelihood of unpleasant urine odours in the home. After the site is identified, urine should be blotted repeatedly with a dry paper towel to reduce the volume at the site. The area should then be infiltrated with a commercially available enzymatic agent designed for this purpose.17,20 Odour-masking agents may satisfy the owner and deter the cat from the area.

Inappropriate Defecation

Treatment of inappropriate defecation includes environmental alterations and behaviour modification. Usually, pharmacotherapy is not required unless the problem relates to generalized anxiety or there is a functional component of marking (discussed in Part II). The environment can be altered by adding a second litterbox for defecation. Qualities of the litterbox may be improved by cleaning it more frequently, increasing the depth of litter, or switching to an unscented litter (Table IV 5,21). It may be necessary to prevent the cat from having access to those areas where it defecated outside the litterbox in order to reestablish appropriate litterbox use.

Table IV
Litterbox Characteristics Affecting Inappropriate Urination in Cats

Litterbox Characteristics


Frequency of cleaning Many cats will reject a soiled box and eliminate elsewhere. Owners who travel frequently, leaving the cat and the litterbox untended for days at a time, may increase the cat's dissatisfaction with the litterbox because of excessive soiling; separation anxiety may also play a role.
Number of boxes A minimum of one litterbox per cat should be available to ensure cleanliness and reduce interference among cats.
Location Remote sites (e.g., a basement) may be inaccessible to an older or infirm cat. Bathrooms and laundry rooms may be associated with excessive noise or odours that may be offensive or frightening.

High traffic areas may be rejected as unsuitable locations.

Box type A covered litterbox may restrict odours to an offensive level or may be too small for large cats to move around in comfortably. The covered litterbox may allow other cats, pet dogs, or young children to target the cat as it exits.
Litter type Preference tests indicate that most cats prefer unscented, fine-grained (clumping) type litter over other substrates.19 Scented litter is more frequently associated with housesoiling problems than is unscented litter.13
Deodourizers Cats may be averse to odours that humans consider attractive. The owner should avoid the use of deodourizers in or near the litterbox.
Number of cats In multiple-cat households, there is a greater likelihood of heavy litterbox use, possibly resulting in an excessively soiled litterbox. Another cat may interfere with the problem cat as it approaches the litterbox, either through odour cues or physically (e.g., aggressive acts or play solicitation in the vicinity of the box).

For clients with good observation skills and patience, positive reinforcement of appropriate litterbox use may be effective. Initially, the cat must be fed twice a day on a regular schedule to determine the daily time of defecation. At the determined time, the client should take the cat to the litterbox and wait until it defecates. The cat should then be rewarded with a special food treat, such as fresh salmon. This protocol should be repeated until the association between the litterbox and defecation is confirmed.22


Feline housesoiling is a common behaviour complaint that causes frustration on the part of the owner and can lead to euthanasia of the offending cat. Successful treatment requires identification of the cat responsible (in multiple-cat households) and of the cause of the problem. Housesoiling can be divided into elimination problems, and marking behaviour. Elimination problems may have medical or .behaviour causes. A physical examination and appropriate laboratory tests are indicated to rule out medical causes or suggest appropriate medical treatment.

A careful behaviour history may reveal the factors) ,contributing to the problem. Common elements include dissatisfaction with some quality of the litterbox, including cleanliness, litter type, or location. Social interference between cats or from other household members may contribute to litterbox aversion. Behaviour treatment is often suggested by the behaviour history. Resistant cases or those involving social factors may benefit from psychotropic drugs (discussed in Part II).


About the Author

Dr. Sherman Simpson is Director of The Animal Behaviour Service of the Veterinary Teaching Hospital, College of Veterinary Medicine, North Carolina State University, . She is a Diplomate of the American College of Veterinary Behaviorists and is Certified as an Applied Animal Behaviorist by the Animal Behavior Society.



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