You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Loss of housetraining  - when a cat starts urinating or defaecating in the house - is a common behavioural or medical problem

When a cat suddenly starts to urinate or defaecate in the house the underlying cause needs to be identified so that appropriate treatment can be given...so veterinary advice should be sought as soon as possible. It is important to keep an accurate history of events ...when did this behaviour start, where is the cat urinating - against walls or furniture (vertical surfaces) or on the floor, how often is the cat defaecating in the house etc.

Common causes of a breakdown in toilet training are :

• Territorial marking - cats back up to vertical objects (eg walls, doors, furniture legs) and spray a small amount of urine on the surface to "mark" it. This type of behaviour is likely to occur inside the home if the cat is being threatened by another cat marking on its territory outside the home
• Inappropriate elimination - urination or defaecation on floors or other surfaces outside the cat litter tray. In this case the act of squatting is normal but may be more frequent than usual. Causes of this include :
  • Medical disorders
    • Defaecation - diarrhoea, colitis, inflammatory bowel disease, 
    • Urination - urinary tract infection eg cystitis, urinary crystals/stones, kidney failure, diabetes mellitus
    • Locomotor problems - neuromuscular diseases
    • Brain disease - loss of cognitive function in old cats, brain tumours
    • Thyroid disease - eg hyperthyroidism
  • Litter tray aversion 
  • Marking behaviour (similar to territorial marking above)

Various forms of treatment can be tried :

• Any medical condition must be treated appropriately by the attending veterinarian
• Litter trays should be cleaned regularly, and positioned in a quiet place to encourage the cat to use them.
• If the cat is going to the toilet in a specific place all the time the litter tray can be moved to that position to encourage use.
• Some cats prefer to go to the toilet on certain materials eg soft cloths or wood....these can be added to the litter tray
• Deny access to rooms in which a cat is soiling - this breaks the behavioural habit and forces the cat to select another place
• The area being used as a toilet can be sprayed with repellents and odour eliminators.
• The area being used as a toilet can be changed to a feeding area  which will deter the cat from using it as a toilet
• Removal of the cat from it's normal environment eg to a cattery or to a Veterinary Hospital may be necessary to re-establish use of a litter tray, and break the abnormal behavioural cycle.
• Neighbourhood cats should be discouraged from entering the garden - eg noise deterrents and use of a water pistol to "shoot" at the cat when it crosses boundaries  into the garden.
• Castration or ovariohysterectomy may reduce spraying behaviour in male and female cats
• In some countries a feline pheromone can be used to deter spraying and marking behaviour
• Drugs can sometimes be used to change the behaviour in some cases :
  • Hormone treatment
  • Anti-anxiety drugs 

Updated October 2013