Inappropriate Elimination - Cat


Inappropriate elimination is a common problem that is often confused with indoor marking behaviour. Differences between inappropriate elimination and indoor marking are discussed in the general section on housesoiling.

Housetraining in cats is the product of innate substrate and preferences, combined with learning during development and the past and current availability of suitable latrine locations. Kittens appear not to learn latrine preferences by observing their mother, but rather by exploring and investigating with available substrates and locations. Failure to provide kittens with suitable latrine substrates can therefore lead to the development of undesirable substrate associations.

History taking should therefore include information about the rearing and early environment, the cat's level of housetraining prior to the problem developing, and information about changes in latrine provision such as switching of litter tray location or litter type. Cats prefer to use their own latrine sites rather than share them with other cats, so any level of antagonism between resident cats is likely to lead to housesoiling.

Normal Elimination Behaviour

To understand the preferences of cats living in a domestic setting, it is important to understand the cat's normal elimination behaviour. Wild and feral cats use separate latrine sites for urine and faeces, and may have numerous latrines located around their peripheral territory. Latrines are located away from hunting, feeding and resting areas. Latrine sites are not shared with other cats, even when cats exist together in a naturally formed colony. The preferred substrate is usually dry sandy soil that is easy to dig. Cats are vulnerable to attack whilst eliminating, so they tend to be secretive.


The presence of urine and/or faeces deposited in the house or outside the litter tray is not definitive evidence of a behavioural problem; medical causes and underlying factors should always be ruled out before reaching a behavioural diagnosis. In multi-cat households, it is therefore important to identify which cat is responsible for the housesoiling. It is extremely unusual for a non-resident cat to enter and eliminate in another cat's home, but this may also need to be considered.

Common causal/contributory medical factors include:

Typical Causes of Inappropriate Elimination

Many of the causes of inappropriate elimination relate to relative unsuitability of available latrine sites. Feral and wild cats have the freedom to choose their own latrine sites, and will select places that provide an acceptable compromise of ideal features that is tolerable to the individual. For example, for some individuals substrate is more important then privacy, and vice versa. In a domestic setting, cats also differ in their tolerance of substrate type, privacy and sharing of latrine sites with other cats, but the range of options that are acceptable to the owner is far more limited. Often inappropriate elimination does not start because a single feature of the litter tray is undesirable to the cat, but because a combination of factors causes the cat to choose another location.

Some common causes include:

  • Inappropriate substrate: Cats appear to prefer unscented, sand-like mineral based litter in a tray filled to a depth of 2-3cm. Scented, pine or wood-pulp based litters are often aversive to cats, although they may tolerate them if other characteristics of the litter tray are acceptable. Litters based on pine chippings have become popular due to owner concerns about biodegradability. However, these release the acrid chemical pineol when wetted with urine. Cats find this deterrent, especially in covered litter trays.
  • Lack of privacy in latrine locations: Cats may refuse to use litter trays that are placed too close to feeding areas or cat doors, or sited in busy places where the cat will be disturbed whilst eliminating. A previously satisfactory location may become unacceptable if the presence of new pets or children constantly disturbs the cat, or if non-resident cats settle in vantage points that overlooks the litter tray location.
  • Competition for latrine sites: Wild and feral cats do not share latrines, and they use separate sites for urine and faeces. In multi-cat households there may be competition for use of litter trays, which can also fill up with urine and faeces, making them unacceptable.
  • Despotism: Some cats show a pattern of despotic control around resources, latrine sites and cat doors, constantly guarding them and intimidating other cats that try to access them. In most cases this is due to a general lack of available resources. Despots may be resident cats controlling resources within the home, or non-resident cats seeking to drive away territorial competitors. Timid, non-assertive cats may choose to use inappropriate latrine sites in the house rather than challenge an aggressive despot.
  • Negative litter box associations: A cat may become reluctant to use a litter tray where it has previously been disturbed or attacked, or where it has experienced pain on micturition (associated with LUTD).
  • Inability to use/find litter trays: Cats with physical debilitation or cognitive dysfunction syndrome may be unable to find or get to latrine sites, especially if they do not have a litter tray and usually go to the toilet outside. They may be unable to make use of high-sided or covered trays.
  • Punishment: Owners may punish cats when they catch them eliminating in an inappropriate location. Cats have not evolved to accept social control over basic functions such as going to the toilet, and are unlikely to associate their specific actions with punishment. They are more likely to find their owner's behaviour intimidating, which can make them wary of eliminating when the owner is present. This can become a serious problem if the cat is is subsequently deterred from using a litter tray when the owner is present.
  • Health problems: Cats with polyuria/polydipsia (PU/PD), incontinence, feline lower urinary tract disease (FLUTD) or recurrent/chronic diarrhoea are unlikely to maintain a normal or acceptable pattern of elimination.

Feline Idopathic Cystitis

Feline idiopathic cystitis (FIC) is a complex condition that involves neurological changes in spinal pain fibres and biochemical changes in the bladder wall. The precise aetiology is not fully understood but there appears to be an association between stress and FIC. Bladder permeability in FIC affected cats is increased by stress[1], and the frequency and severity of signs is associated with stressors such as conflict with another resident cat[2]. Cats with FIC also appear to show differences in their response to stimuli, being more stress responsive and easily startled by noises[3].Cats with FIC exhibit a characteristic set of sickness behaviours that are the result of inflammatory cytokine activation[4].

This indicates a strong connection between aspects of temperament, environmental stressors and FIC, which has led to the adoption of a multimodal strategy for the treatment of the disease[5].

FIC should therefore be considered an important underlying factor in inappropriate elimination in cats.


Medical Factors

Causal and contributory medical factors should be investigated and treated. Conditions such as FIC should be ruled out.

Environment Issues

Common environmental changes that precipitate inappropriate elimination include:

  • Change of litter type.
  • Relocation of litter tray.
  • Switch from uncovered to covered litter tray (or vice versa).
  • Relocation of other resources (e.g. feeding bowl moved closer to litter tray).
  • Installation of household equipment (e.g. noisy washing machine or boiler close to litter tray).
  • Increase in household disturbance or noise levels (e.g. due to building).
  • House move.

Typically, it is possible to identify one or two environmental changes that have precipitated the inappropriate elimination problem. However, it is very important not to treat the problem at this superficial level. If a single apparently inconsequential change has triggered a period of inappropriate elimination then it is very likely that there are other underlying problems that also need to be addressed. Not to do so may leave the cat vulnerable to welfare and behavioural problems in the future, and an incomplete or temporary resolution of the current problem of inappropriate elimination.

The presence of a problem of inappropriate elimination should be regarded as an indicator of general environmental inadequacy, and an opportunity to review the cat's living conditions.

The amount, choice and distribution of resources should be reviewed and improved, for example:

  • Provide ad-lib food where possible, preferably in more than one site and using activity feeding devices.
  • Increase the number of places to climb, hide, claw and rest.
  • Provide a choice of outdoor access points if there are signs of competition around the cat door.
  • Install an electronic coded cat door that only permits access by resident cats (especially if there is evidence that non-resident cats have been coming into the home.

If there is a garden, this can easily be adapted to provide environmental enrichment for the cat, reducing pressure on indoor resources for multi-cat households.

If factions have been identified in the household, resources should be distributed so that each faction has access to a full set of its own resources in a location that it tends to favour. Distributing resources around the home also prevents resident despots from being able to monopolise resources and intimidate other cats. This also helps to undermine the activities of feline despots who try to monopolise specific resources.

Litter Tray and Latrine Sites

Although cats vary in their specific preferences, and their tolerance for particular defects in litter tray provision, a general guide for litter tray provision in problem cases would be as follows:

  • High sided tray that is large enough for the cat to turn around in (many trays are not large enough).
  • Unscented, fine grained, mineral based litter.
  • Located where the cat can access it easily, but without be disturbed whilst eliminating.
  • One litter tray pet cat, plus one extra (to allow cats to avoid sharing latrines).

Cats show no general preference for covered or open litter trays[6], so a choice should be provided until the cat's preference is established.

A commonly overlooked aspect of dealing with inappropriate elimination problems is the potential to provide cats with designated outdoor latrine facilities. The commonest complaint about neighbourhood cats, by cat owners and non-owners alike, is that they defecate in people's gardens. However, most cat owners do not provide either a litter tray or a suitable garden location for a toilet. The owner's garden may be mostly patio or grass, neither of which is a suitable toilet location. All owners should be encouraged to install outdoor cat toilets, or to create an area that the cat can use. A typical outdoor cat toilet can be prepared as follows:

  • Choose an area in a border or flowerbed where the cat can have some privacy.
  • Dig a hole that is about the size of a cat litter tray, but 30-60cm deep.
  • Fill the hole with soft playground sand (not sharp sand that is commonly used for construction purposes).

Deterring Inappropriate Elimination

If suitable latrines have been provided, and the general environment has been improved for the cat(s), then it is acceptable to use mild deterrents to encourage cats to stop using inappropriate elimination sites. The best indication of what measures may deter the cat is the reason why it chose that location to begin with, for example:

  • If the site has been chosen for increased privacy: Restrict or block access to the location, or install a radio or bright table lamp that illuminates the area. Battery powered infra-red activated lamps can also be used; these switch on as the cat approaches.
  • If the site has been chosen for substrate: Cover the area with aluminium foil, double sided adhesive tape, or polythene that make the surface unpleasant to stand on.
  • If the site has been chosen to avoid eliminating near other resources: Place small bowls of food close to the location so that it becomes designated as a feeding station instead of a latrine.

Social Issues

Social problems can originate with resident and non-resident cats. In areas of high cat population density, non-resident cats may compete with resident cats for outdoor space and latrine sites. They may even enter the home to steal food, which not only depletes resources for the resident cats but may also deter them from accessing other nearby resources (such as a litter tray). A secure, coded cat door that prevents access by non-resident cats should be installed. It should be fitted with an opaque door, or the door should be painted or covered with film so that non-residents cannot see into the house.

Conflict between resident cats can be identified using the interaction diagram shown in the overview section on housesoiling. Apart from providing each cat or faction with its own set of resources, it may be possible to improve cohesion between all group members by the creation of an enhanced group odour. Cats identify each other through the use of allorubbing and allogrooming to create a common odour signal that identifies all members of the group. Factions within a household may not allorub and allogroom, so they do not share a group odour. The owner can deliberately transfer odour between group members through grooming. The core territory of cats is a location where they do not expect to encounter unfamiliar cats, and where they do not usually eliminate. The use of a F3 (Feliway) diffuser may help to strengthen the core territory pheromone marks, and thereby reduce stress and social conflict between resident cats.

Psychoactive Drug Therapy

Cats that are anxious, inhibited, or fearful may be unable to utilise an enriched or altered environment, or adapt to change. They may benefit from treatment with psychoactive medication.

In the dog, selegiline is licensed for the treatment of behavioural problems with an underlying emotional cause (UK and EU license). It is not licensed for use in the cat, but could be used in accordance with CASCADE. This drug increases exploratory behaviour and decreases apprehension. It can take up to 8 weeks to reach efficacy, but typically some improvement is seen after 4-6 weeks in cats.

Selegiline has minimal anxiolytic effects, so for cats with generalised anxiety or signs of panic a serotonergic drug such as fluoxetine or clomipramine may be preferable. Clomipramine is licensed for the treatment of separation anxiety in the dog, but not licensed for use in cats.

Neither selegiline nor serotonergic drugs have a specific indication for inappropriate elimination; they are used to alleviate underlying emotional problems that contribute to the problem. Long term drugs of this kind should be continued until the cat is fully utilising resources and has not eliminated in the house for 6-8 weeks.

Treatment of Inappropriate Elimination
General environmental and social issues:
  • Increase amount, choice and distribution of resources available to the cat(s).
  • Locate resources for easy access by the various cats and factions within the household.
  • Give the cats indoor-outdoor access with a secure electronic coded cat door.
  • Provide food ad-lib, preferably using activity feeding.
  • Provide more choice of resting and hiding locations.
  • Install F3 diffusers, to reduce stress due to inter-cat tension in multi-cat households, and provide a stronger pheromonal signature for the core territory.
  • Use scent swapping to improve group odour.
  • Consider temporarily isolating and then reintroducing cats if there are problems of aggression.
Latrine number, location and substrate:
  • Latrines should be relocated to quiet areas.
  • Litter trays should be deep filled (3cm) with a mineral-based or clumping litter (not pine or wood-pulp based or scented).
  • In some cases using pure sand or a 50% mixture of litter and sand as a substrate in trays, is attractive to cats.
  • A mixture of covered and open litter trays may be trialled.
  • Additional outdoor toilets should be provided.
  • Total latrine number may need to be as many as one per cat plus one extra.
  • A specific latrine location may be made to feel more secure by locating an F3 diffuser (Feliway) next to it.
Owner behaviour:
  • Stop punishment of inappropriate elimination.
Psychoactive drug therapy:
  • Selegiline: specific fear with behavioural inhibition that limits normal behaviour
  • Clomipramine/Fluoxetine: chronic anxiety (concomitant signs of stress such as over grooming).
  • Clomipramine/Amitriptylline: FIC


The prognosis for cats with house-soiling problems is good, as long as owners can accept that there may be brief relapses in the future. Even if the domestic indoor and outdoor environment is optimised and relationships between cats in the household have been improved, there is always the possibility that new cats to the neighbourhood may upset the situation.

Cats with a history of inadequate housetraining, or inappropriate substrate or location preference are likely to relapse on occasion during periods of stress, or if the owner makes changes to existing toilets. These cats may always be a short step from reverting to using their own preferred toilet sites so it is important to stick to environmental modifications that work.


  1. Westropp, J.L., Kass, P.H., Buffington, C.A. (2006) Evaluation of the effects of stress in cats with idiopathic cystitis. "Am J Vet Res.". 67(4):731-6.
  2. Cameron, M.E., Casey, R.A., Bradshaw, J.W., Waran, N.K., Gunn-Moore, D.A. (2004) A study of environmental and behavioural factors that may be associated with feline idiopathic cystitis. "J Small Anim Pract". 45(3):144-7.
  3. Hague, D.W., Stella, J.L., Buffington, C.A. (2013) Effects of interstitial cystitis on the acoustic startle reflex in cats. "Am J Vet Res". 74(1):144-7.
  4. Stella, J.L., Lord, L.K., Buffington, C.A.T. (2011) Sickness behaviors in response to unusual external events in healthy cats and cats with feline interstitial cystitis. "J Am Vet Med Assoc". 238:67–73.
  5. Buffington, C.A.T., Westropp, J.L., Chew, D.J., (2008). Clinical evaluation of multimodal environmental modification (MEMO) in the management of cats with idiopathic cystitis. "J Feline Med Surg". 8:261–268.
  6. Grigg, E.K., Pick, L., Nibblett, B., (2013) Litter box preference in domestic cats: covered versus uncovered. "J Feline Med Surg." 15(4):280-4.

Also see:

Housesoiling - Cat
Indoor Marking - Cat

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Last modified on 16 July 2015, at 09:46