Impurity in Cats – What Causes It?

When the cat leaves puddles in the house, the guesswork often begins: What is the cause of the sudden uncleanness?

Risk factors: Not scientifically clarified

Impurity (perineurial) in domestic cats is often difficult to manage. On the one hand, several risk factors have been postulated, on the other hand, the importance of individual factors is often difficult to assess in a specific case. In addition, the therapy-relevant distinction between marking and urination is not always trivial. An online survey of pet owners shows the complexity of the topic.

Problems with marking and urination are common

About half of the 245 evaluated questionnaires reported unclean cats, about a third with “marking” and two-thirds with “urinating”. In these groups, the presence of 41 potential risk factors and 15 differentiators for marking/urination were assessed statistically.


The most prominent risk factors for impurity were:

  • age (marking cats were older than the other two groups),
  • many cats in the household (more marking/urinating),
  • unlimited clearance and cat flaps (more marking),
  • General clearance (less urination),
  • defecation outside the litter box (more urination),
  • strong dependence on the pet owner (less urination) and
  • a relaxed nature of the cat (less marking).

The best way to differentiate between marking and urinating was by using the characteristics “posture when urinating” and “burrowing”; the choice of surface (horizontal/vertical) and the amount of urine passed were somewhat less meaningful.


The presence of a single risk factor was generally not a reliable indicator for the diagnosis. The overall social environment of the cat appeared to be more important.

This includes a combination of the number of cats in the household, the cat’s bond with the pet owner, and the nature of the cat. But the presence of a cat flap can also have a significant impact on the social environment. The physical conditions in the environment, on the other hand, played a subordinate role.

Frequently Asked Question

Why do cats suddenly become unclean?

In principle, uncleanliness can be triggered by changes, for example, a move. New members of the household, either through the birth of a child or the arrival of a new partner, can mean that the cat feels compelled to mark its territory.

Why does my cat pee on everything on the floor?

Cats are very clean and don’t want to do their business in a dirty place. So it’s possible that your kitty doesn’t find her litter box clean enough and prefers to pee on things that are on the floor.

Why does my cat stink from the anus?

Every cat has what are called anal glands in the rectum, which are usually emptied when your cat pooes. If these anal glands become inflamed, they may leak and give off a very intense and unpleasant smell.

Why does my cat run around the apartment at night?

The reason for the cat’s behavior is very simple: it has too much energy! Cats are known to spend two-thirds of the day sleeping – that’s a good place to gather strength. Excess energy is then drained off instinctively.

Why does my cat follow me everywhere?

Cats that follow their human everywhere often beg for their attention. They run in front of your legs, roam around your human and charm him with cooing and soft meowing. The cat often shows this behavior to signal that it is hungry.

What smell do cats dislike?

Cats don’t like the smell of citrus fruits, rue, lavender, vinegar, and onions. They also dislike naphthalene, paprika, cinnamon, and the smell of a dirty litter box.

What is protest peeing in cats?

So-called protest peeing is just a myth. For cats, feces and urine is nothing negative and also not disgusting. For them, it serves as a means of communication. In the wild, boundaries are marked by the release of feces and urine.

What to do if cats pee in protest?

Rustling foil, newspaper, or bubble wrap can be uncomfortable for the cat so it avoids the laid-out areas in the future. If the cat can also be caught red-handed, it should be startled while urinating. This succeeds either with a loud call or by clapping your hands.

Mary Allen

Written by Mary Allen

Hello, I'm Mary! I've cared for many pet species including dogs, cats, guinea pigs, fish, and bearded dragons. I also have ten pets of my own currently. I've written many topics in this space including how-tos, informational articles, care guides, breed guides, and more.

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