Cat sitting in litter box

Everything You Never Wanted To Know About Cat Urine

Cats are glorious creatures. Motion optimized, aesthetically pleasing, low maintenance, warm, fuzzy, furry, cute, and they purr. I mean, come on, could you ask for a more perfect pet?

In this cat lover's opinion, cats have only one major design flaw: kitties were designed with a poorly functioning elimination system. Specifically, their kidneys are weak, they don't drink enough water, and the cat urinary tract suffers frequently from disease.

The kidney issue, I will talk about another day. For now, let's talk about Feline Urologic Syndrome (FUS) aka Feline Lower Urinary Tract Disease (FLUTD)aka Feline Idiopathic Cystitis or Feline Interstitial Cystitis aka "if it has more than one name, that probably means we don't know what causes it".

Cat Urinary Tract Disease is the Curse of a Veterinarian's Existence

Cat urinary tract disease is a big problem. I can summarize 90% of my sick cat visits in one line: "Doctor Magnusson! The cat just peed on my Persian rug / pile of laundry / fancy purse / kid's backpack / bed sheets and I'm seriously considering making her an outside cat or euthanizing her or sending her back to the shelter if you don't FIX HER RIGHT NOW!"

Boy, I hear you. Nothing stinks like cat pee.

If, for some reason, I were an evil genius and decided to invent a disease to torment both veterinarian and patient, that disease would:
- Occur in otherwise young, healthy patients
- Have no definable cause
- Have no reliable prevention
- Have no known cure
- Be potentially lethal
- Cause thousands of dollars in property damage
- Cause everyone around the patient emotional stress
- Fill up overcrowded Humane Society buildings

I could go on, but you get the idea. I feel your pain. Call it what you want, cats who pee on stuff are no fun for anyone. Inappropriate urination is the #1 cause of cat surrender to animal shelters.

Cute ginger cat lying on bathroom floor, covered with green rug.

Cat Urinary Tract Illness Affects A Lot of Kitties

It has been estimated that at any given time, 1.5% of all kitties in the US suffer from a cat urinary tract disorder. If we conservatively say there are at least 60 million American homes with cats, that means that right now, somewhere, 900,000 American cats are straining to pee on a bathroom rug. So it's not just your cat, the neighbor's cat is doing it too.

If you have a cat, chances are at some point you've had to deal with cat pee in places it's not supposed to go.

It's frustrating. I totally get it. Our human temptation is to label this behavior with human traits, and say the cat is either angry at us, or frustrated, or vengeful, or just mean. Naturally, cats aren't capable of any of these emotions.

Cats love peeing on bathroom rugs. It's like, their favorite thing. Why?

Rule out Medical Causes of Inappropriate Urination FIRST

PRO TIP: Fewer than 2% of Inappropriately Urinating Cats have a Bladder Infection

Humans have been trained by our physicians to think that if something is bothering one's bladder, it must be infection. But in cats, that's simply not true.

If we were to look at a population of 100 cats presented for medical bladder problems, 2% of them would have a bacterial UTI. And, despite what the pet food industry wants us to believe, only 20% have struvite or oxalate crystals in the bladder causing irritation (which can often be managed with diet). That means that 78% of all cats presented for symptoms related to the cat urinary tract or inappropriate urination have NO infection, NO crystals, NO cancer, NOTHING. Just a little bit of blood, really sad and frustrated owners, and a trail of destruction at home. Cat bladders just get grumpy sometimes, for no darn good reason at all.

Now, that's not to say I won't send home antibiotics and/or a prescription diet for most cases of cat urinary tract disease, because I most certainly will. The point I'm trying to make is that one must NOT EXPECT the antibiotics or diet or ANYTHING ELSE (don't even get me started on natural remedies) to solve the problem immediately, nor can one expect the issue won't recur, because there's a good chance it might. Rational expectations are the key to success, when it comes to illness of the cat urinary tract.

So what causes the cat bladder wall to suddenly bleed and shed cells and irritate the cat to the point he/she has to pee on your stuff? Nobody knows. They just do that. And why, when the cat urinary tract and bladder is irritated, does that irritation force the cat to pee outside of the litterbox? Why can't they strain INSIDE the litterbox?? I don't know. I wish I knew. When a cat feels bladder pain, they like to share their suffering with others. Cats are funny like that.

The bottom line to this discussion is simple: if something is bothering your kitty, take her to the vet. But when you do, keep an open mind. Vets are not just antibiotic-dispensing machines, we have other tricks up our collective veterinarian sleeves, and the problem may not be infection. The cat urinary tract is a mysterious beast and deserves our respect and patience to treat.

Your veterinarian will likely rule out medical causes of bladder irritation with a series of routine tests.

A complete physical examination, a urinalysis, a bacterial culture of the urine and X-rays of the bladder must be performed, to rule out medical causes of inappropriate urination before we make the dreaded diagnosis of "behavioral".

Please let your vet do these things before reading further.

Tabby cat near litter box

The Dreaded "Behavioral" Diagnosis

Cats do not pee on your stuff because they are mad at you. Cats are incapable of anger, jealousy, or any of those other myriad emotions we swear they feel.

A cat that urinates on your stuff is anxious about something, pure and simple.

To get to the source of the anxiety, one must think like a cat. Be the cat. See the world through the cat's eyes.

Treating a Cat with Behavioral Inappropriate Urination

Why do cats pee when they're anxious?

Well heck, I don't know. I'm not a cat psychologist, I'm just a vet. But alas, that's what they do.

Treating these cats involves somehow making your cat's life less stressful. Sometimes that means give him a cleaner, bigger litterbox, sometimes it means more love and attention, sometimes it means Prozac.

Before we get into drugs, there are a few universal rules about inappropriate urination in cats that you should keep in mind:

  1. Cats value independence. In multiple cat households, each cat will often choose a preferred box, mark it with their urine, and refuse to use each other's boxes. Buy one more box than the number of cats in your home.
  2. Cats value safety. Every cat in your house should have safe access to a litterbox without interference from house mates, because nothing stresses out a cat more than another cat. Sometimes cats will ambush another cat when they step into or out of the litter box. Put another way: If Cat A is standing in the one and only doorway to the litterbox room, it makes sense that Cat B might sometimes pee on your bathroom rug rather than risk a fight with Cat A. Does your box have a cover? Perhaps having that cover makes your cat feel trapped. Watch your cats. Do they "lie in wait" for another cat to go in and then pounce? If you are able, put each litter box in a separate room, and/or on separate floors.
  3. Cats value privacy. Put those litterboxes in quiet, stress free places. Sometimes that means your bathroom, sometimes it's in a closet. Rarely is it beside the washing machine or furnace or other loud appliance.
  4. Cats value their own personal space. It's been said that in a home with five cats, the probability of having to deal with inappropriate urination by one of those cats approaches 100%.

OK, so that's all you need to know about inter-cat communication. Now let's talk personal preference.

  1. Cats value cleanliness. Your cat spends most of her waking hours cleaning herself, do you think she wants to walk through last week's pee residue on the bottom of her litterbox? Or worse yet, a housemate's pee residue? Ew. Too few litter boxes can get soiled very quickly and a fastidious cat may not want to step inside. Scoop every litterbox at least twice daily. Thoroughly empty and scrub out the boxes and refill with clean litter at least weekly. Cleaning a litterbox is a pain, but it's a sure sight easier than cleaning cat pee off your stuff.
  2. Cats value consistency. Most cats will develop a preference for the feel of their litter, and 99% of them will end up preferring clumping clay litter. Change your cat's brand or type of litter at your own peril.
  3. Cats value their sense of smell. Some cats will refuse to use heavily perfumed cat litter. Litter labeled as "multi cat household" simply has more perfume added to it; if your cat is having a urine problem, try unscented clumping clay litter instead.
  4. Cats value pheromone signals. If something has changed in your home - position of furniture, new people, old people leaving - consider adding Feliway pheromone to the mix. Feliway is a concoction of the pheromones cats rub on you with their face, which they do to mark familiar and safe territory. Feliway can convince some cats that new things are as safe as old things.

Special Note on Spraying

Cats that back their butt up to a vertical surface and wiggle their tails and pee sideways, are marking the object. Neutering often helps, if done early enough in life, though sometimes cats will get in the habit of urine marking and you'll have a harder time breaking them of this habit. Consult an animal behaviorist for help.

Spraying is not the same as inappropriate urination. Spraying is a marking behavior, inappropriate urination is an anxiety behavior.


  • cat behavior
  • Cat Wellness