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Cat Toileting Issues: Undesirable Elimination Behaviour

Toileting problems in cats: Approach to “Undesirable Elimination” 

As a new cat mum, we thought we'd hit the jackpot with a wondrous kitten! She would use her litter tray every single time and kept things tidy aside from tracking small amounts of litter.


And then IT happened: a few deposits on the thick mat placed under her litter tray, not just once but a few days in a row! We did not think we had done anything differently; we scooped both her trays daily so what could possibly have gone wrong?

This left us scratching our head in puzzlement and we sought out the expert advice of Vet Behaviourist Dr. Elle Parker from Pawly Understood.

Toileting problems in our feline friends are common, frustrating and very messy (pun intended). Toileting issues can manifest as voiding of urine and/or feces deposited outside of the litter box, or marking behaviours such as urine spraying.

This umbrella category of problems has previously been called “inappropriate” elimination. However, we need to remember that the behaviour is not “inappropriate” for the cat (only the owner). So, this terminology has been discarded among behaviour professionals and given way to the term “undesirable” elimination behaviour.

Key point: Feline undesirable elimination is the most common behavioural complaint of cat owners. Sadly, it is a significant causal factor for premature euthanasia. For this reason, we need to better understand why it happens and what we can do to help.

Step 1: Make sure you’ve got the correct culprit!  

Here you go mum! I'm holding down that culprit for you ...
Determine which cat is eliminating when there is more than one cat.

When there are multiple cats in the home, it may be difficult to determine who is actually soiling. Confinement of one or more cats may be necessary to discover who is not using the litter box.

A special dye can be administered to one cat, and the soiled areas can then be evaluated with a special light to determine if that is the cat that is house soiling. 



Setting up a covert "kitty camera" is also really important. Capturing footage of which cat is doing the behaviour as well as observing the actual toileting behaviour is a fundamental part of this work-up process.

Step 2: Establish whether the undesirable toileting is marking or voiding!

This is important as they have different causes and therefore different treatments.

1) Marking:

  • Purpose: to communicate to others one's presence, delineate territorial boundaries, show passive aggression towards other cats outside of social group (to avoid actual fighting), self-soothe if anxious or fearful.
  • Deliberate overt toileting usually in socially significant / obvious areas. 
  • It usually involves sprays of small volumes of urine (not emptying whole bladder). 
  • Usually urine is sprayed on to vertical surfaces or faeces placed in prominent locations (doorway, hallway, middle of room). 
  • Specific distinctive behavioural repertoire displayed during spraying: cat backs up to wall or object, tail quivers, may appear trance-like, may vocalise, may knead the paws, ejects rapid squirt of urine. 
  •  Cat usually still uses its litter tray sometimes - then sometimes urinates / defecates elsewhere. 

2) Voiding:
  • Purpose: to empty bladder / bowels.
  • Often will be done in private in secluded areas. 
  • Usually involves large amounts of urine / faeces in puddles / piles. \
  • Usually on a horizontal surface. 
  • Cat may make attempts to bury or cover the deposited material. 
  • Cat usually squats discretely. 
  •  May not do any urinations or defecations in the tray 

Step 3: Rule out medical causes!

Book in to see your vet.

Medical diseases of the urinary tract 
(e.g. FLUTDcan cause abnormal elimination. There are many such conditions, including stones and crystal formation in the bladder, bacterial infections, and a group of inflammatory diseases of the bladder and urinary tract which cause pain and an increased urgency to urinate. 
Diseases of the kidneys and liver can cause the cat to drink more and urinate more frequently. 

Some metabolic and hormonal disturbances (such as diabetes and hyperthyroidism – both of which are common in cats) also cause excess drinking and urination. In addition, age related cognitive (brain function) decline could lead to changes in elimination habits including house soiling.

Medical problems that lead to difficulty or discomfort in passing stools, poor control or an increased frequency of defecation could all contribute to house-soiling with stools. Colitis, constipation, and anal sac diseases, are just a few of the medical problems that need to be ruled out when diagnosing the cause of undesirable defecation.

Another consideration is the pet’s physical mobility and sensory function. Medical conditions affecting the nerves, muscles, or joints, could lead to enough discomfort, stiffness or weakness that the cat may not be able to get to the litter box, climb into the litter box, or get into a comfortable position for elimination. 

It is a huge ask for old weak arthritic painful cats to climb over the high edges of a litter tray and squat to do their business!

So generally, if elimination is associated with pain or discomfort, or if access to the litter box is difficult or uncomfortable the cat may begin to eliminate outside of the box. 


In addition, those cats with increased frequency of elimination (especially if the litter box is not cleaned more frequently) and those with decreased control may begin to soil the house. The soiling in the home is often the first sign of clinical disease that an owner notices.

A complete physical examination, urinalysis and in some cases additional diagnostic tests such as blood tests, radiographs or a urine culture, will be needed to rule out medical problems that could be causing or contributing to the cat’s elimination problem. Some problems may be transient or recurrent so that repeated tests may be needed to diagnose the problem.

Step 4: Investigate psychological causes. 

Once medical problems have been ruled out, mental health needs to be scrutinised next. 

Stress and anxiety are very common causes of behaviour problems and toileting issues in cats. Anxiety and chronic stress are very harmful to many systems in the body. Anxiety is a serious disease.

Cats are sensitive creatures. Stress will often manifest as behavioural or physical disturbances. Undesirable elimination is one of these manifestations. Cats who are anxious will often mark with urine as a coping strategy to feel more secure in their environment – it can be considered a self-soothing behaviour.

Stressed cats even need to urinate more often and have more dilute urine because stress hormone interferes with processes in the kidneys which concentrate and conserve urine.

As well as the toileting issues, there may be other clues your cat is stressed and anxious such as hiding, avoiding things, being over or under-active, not playing, changes in appetite, excessive grooming, losing hair, fighting with other cats in the home, social changes such as being grumpy / irritable or aggressive.

So what causes stress and anxiety in cats?

Cats, like most species, can suffer many forms of anxiety and emotional disturbances which cause significant physiological stress and abnormal behaviour. Cats can be afflicted with mental illness – just like people.

Examples include: specific fears and phobias, generalised anxiety disorders, post-traumatic stress disorder, noise sensitivities, separation-related anxiety, obsessive-compulsive disorder, social anxiety and aggression.

Like any behavioural problem, toileting issues are complicated and are caused by 3 overlapping factors:

1) GENETICS
2) EXPERIENCE / LEARNING
3) ENVIRONMENT / CONTEXT


So, there is no one reason why your cat is doing a behaviour – it is always a combination of the above factors interacting to produce the final behavioural outcome.

For example, a genetically resilient cat may suffer severe hardship and stress and develop an anxiety disorder. Meanwhile, a genetically susceptible cat may be prone to anxiety but never develop a problem due to having a very suitable, stable and safe environment, free from stress.

It is worth understanding that cats are generally creatures who do not cope well with change or disruptions. They are also innately territorial, often with closed and strict social groups. They are usually reluctant to accept new individuals who they have not been socialised to as a youngsters. When we expect cats to live together harmoniously in our houses this is often unrealistic and can sometimes be highly detrimental to one, many or all cats involved.

In cases where toileting is an issue, the relationships between the soiling cat and other animals and people in the home need to be examined closely. Social stress is a huge contributor to these issues.

Major common factors contributing to anxiety:

✔️ Social changes in the home: eg arrival of new partner or baby, arrival of a new pet, death of a pet. 

✔️ Physical changes in the home: eg moving house, new furniture, new bedding, new diet, changing from indoor to outdoor access etc 

✔️ Routine disruptions: eg change in work schedule
✔️ Seasonal variations: inclement weather
✔️ Stray cats or other animals around the home
✔️ Noises or vibrations – many cats get stressed when there is nearby construction work.

How is anxiety treated in cats?


This is a complex question and is discussed in more detail in previous publications.

To simplify, anxiety can and should be treated using a multi-angled approach called the “4 Ms”:

- Management: environmental control to provide for the needs of the cat and reduce stress.
- Modification: changing emotions and therefore behaviour via structured re-learning and training.
- Medication: using medicines to correct disturbances in the brain and body associated with stress and anxiety.
- Monitoring: objectively noting and recording changes in behaviour so it is clear whether treatment interventions are working.

These angles of treatment together aim to address all of the causative factors of behavioural problems discussed above (genes, learning, environment).

There are even some other adjunctive treatments which can be helpful in many cases such as pheromones and nutritional supplements.

Your vet can talk you through specific tailored relevant treatment plans for your pet depending on the type and severity of their problem.

Step 5: Consider other behavioural causes:

Is the toileting behaviour a choice?

When all medical problems (including mental illness / anxiety) have been treated or ruled out and the house soiling persists, a complete and comprehensive behavioural history will be necessary in order to establish what is going on. In these cases, the cat for some reason, is electing to toilet outside of its provided litter tray. We will need to collect information about the home environment, litter box type and litter used, litter box maintenance and placement, and the onset, frequency, duration and progression of problem elimination behaviours.

There are 6 diagnostic possibilities for why cats may choose to toilet outside their litter tray:

1) Substrate aversion: they do not like the litter type in the box
2) Substrate preference: they have discovered a new surface to toilet on which they like more than their normal litter (eg glossy tiles, fabric, carpet, wood etc)
3) Location aversion: they do not like the spot where their litter tray is
4) Location preference: they have discovered a new and more likable spot to toilet elsewhere (eg it may be more private or more comfortable)
5) Litter box aversion: they do not like using the tray itself (eg it may be too dirty, too smelly, too small, too uncomfortable, too unstable, too tricky to get into or out of etc). NOTE: In some cases it may now be too scary to use the normal toilet area i.e. if something unpleasant happened there! If cats have had negative experiences in their litter box (eg they experienced pain or a fright) then they may begin to avoid it!
6) Incomplete toilet training: the patient may have never had consistent toilet training and may have never developed a solid preference or acceptance of using a litter tray. This can be the case for cats who are used to toileting outside or who were strays or rescues.

Step 6: Once I know what's going on, what should I do about it?

If the cause is behavioural then there are 4 things that need to be addressed to make sure you provide the perfect toilet for your cat to attempt to re-train it to use the litter tray on your terms.

✔️ Basic toilet training 
✔️ Litter tray factors

  • Hygiene / maintenance / cleaning
  • Size / shape 
  • Covered vs uncovered 
  • Steady / stable 
✔️ Litter type / substrate: what’s in the box? 
✔️ Litter tray location/s. This also includes how many different trays are provided. 

#1. Toilet training: 


First consider the cat’s background and whether it may or may not have ever learned to use a litter tray. This may be of relevance for a new cat. In many cases though, elimination issues suddenly develop in a cat who has always used the litter tray reliably until now.

#2. Litter Tray:


Litter box maintenance and hygiene is paramount! For some cats, it is necessary to keep the litter box scrupulously clean as they are very fastidious. 

This may mean changing the box daily, or at least removing feces every day
Remember, in the wild, cats would not continue to use the same place to toilet all the time for risk of parasite contamination and re-infection – avoiding your own feces is best! 

Cleaning the litter tray: This should be done at least weekly – all the material should be discarded and the tray cleaned with dilute detergent or boiling water. 


Don't use heavily fragrant chemicals. Cats may be reluctant to use the litter box if it has been recently de-odourised if the cat dislikes the odour of the cleansers (so rinse well after cleansing). If the same litter box has been used for several years, discard and get a new one.

Regarding the size of the tray, most commercial litter trays are FAR TOO SMALL

A tray should be generous in size and at least 1.5x the length of the cat (that includes the extended tail!). The cat should be able to turn around and dig in the tray. Use a large lid or other appropriately sized storage box rather than a designated litter tray if it is a better size. 

Some cats have a preference for whether the box is covered or uncovered. A covered tray can give them privacy and make them feel secure or may in fact make them feel trapped and worried. A covered tray also traps odours and chemicals.

Importantly, the tray needs to be secure and stable. If it is on uneven ground and moves when the cat gets in or when it's scratching around, this can be a deterrent.

#3. Litter Type


The choice of litter material is important and is very individual for each cat.

Some cats prefer clumping litter and some non-clumping. Some prefer fine and some coarse substrate. Some prefer absorbent and some non-absorbent materials. Some cats need lots of material and some only a little. As a general rule, many cats prefer natural substrates such as sand or soil. 

A litter tray “buffet” should be offered to determine what your cat likes - different shapes, sizes and litter types. 

Note which the cat prefers to use. If the cat has been toileting on certain surfaces such as fabric / carpet then samples of these should be put in a litter tray to encourage the cat to recommence using the tray – it can then be slowly transitioned to litter again later.

#4. Tray Location


The location of the litter box also needs to be addressed. Some cats may be unwilling to use a box that is difficult or inconvenient to access (eg up or down stairs or up high on a shelf / table). The box may be located in an area that the cat finds unappealing or unpleasant. 

Lighting and airflow makes a difference as some cats don't like areas which are too bright or too dark, some don't like drafts. Most cats like a private area away from foot traffic
Most cats won't tolerate excessive noise nearby – a washing machine on spin cycle in a laundry can be very scary and off-putting! 

Often cats like to use trays with at least 2 escape points ie not enclosed on 3 sides. If cats have had previous traumatising experiences in their litter tray (being attacked by another cat, something falls on them, lightning strikes outside etc) they may not be comfortable using that same spot ever again.

Encouraging cats to move locations can be achieved by trying the following:

1) Soiled locations MUST be cleaned appropriately so that odour molecules are destroyed and the cat is not tempted to continue re-using this spot. An enzymatic cleaner must be used – there is a commercial one called “Urine Off” for sale which works well. DO NOT use ammonia based cleaning products or bleach – these smell like urine to cats and may encourage the cat to keep toileting in the cleaned area.

2) Put a litter tray buffet in the place they are currently toileting - then once they are using it reliably, gradually move the litter tray back to where you would like it to be long term – slowly and steadily.

3) Put other important resources where the cat is toileting: Place food / water / scratching posts / bedding in this region so that it is less consistent with a toilet and takes on a different significance to the cat. 


4) Use management to restrict the cat’s movement – block off the areas of concern and confine the cat to offer a litter tray buffet. This serves to re-train the cat to use a box by limiting its options – However this may be stressful to some cats and needs to be monitored.

5) Supply more toilets! When there are multiple cats in the home, multiple boxes in multiple locations will most likely be needed.

o As a general rule there should be one toilet per cat + at least one extra. They must be spread out in different spots (not all lined up together or in the same room – this counts as only one toilet!).

o Where social tension exists and cats do not get on well (are not in the same social group) then there can be conflict over important resources – of which toileting area is one! They often are not comfortable sharing a toilet unless they are very close friends.

If the above recommendations do not resolve the problem, then the patient must have a thorough re-assessment by a behavioural veterinarian to diagnose and correct the issue.


written by Dr Eleanor Parker, November 2019 for Australian Cat Lover (all rights reserved)


For questions, clarifications, further information or if you know a dog with separation anxiety who needs help, please contact Dr Eleanor Parker of Pawly Understood. 


About Dr Eleanor Parker
BSc BVMS (Hons) MANZCVS (Behaviour)

Elle graduated from Murdoch University in 2010. Starting out in emergency and critical care, she quickly found her passion for behaviour and mental health in animals.
Fascinated by this blossoming field, Elle undertook further study through the University of Sydney in 2015 and sat her membership exams in veterinary behaviour in 2016.

Elle's behavioural mantra is "compassion, communication, co-operation, cohabitation". She offers private veterinary consulting services to people needing assistance with their pets' behaviour through her practice at Pawly Understood.
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