Top Veterinarian Reveals The Real Reason Cats Spray In Multi-Cat Homes (And The Simple Fix That Finally Stops It)

July 17, 2026 at 9:32 am AEST

I've been a vet for 15 years, and I need to start by admitting something.

For a long time, I was giving cat owners the wrong advice.

Not on purpose. It was the same advice every vet gives, the advice I was taught. But it didn't work, and it took me years and one particular cat to understand why.

I'm talking about spraying. A cat marking around the house in a home with more than one cat.

It's one of the most common problems owners bring to me, and one of the most misunderstood.

Roughly 1 in 10 male cats and 1 in 20 female cats will spray at some point, and in multi-cat homes the odds climb sharply.

It is also one of the top behavioural reasons cats are given up to shelters, not because owners stop loving them, but because they're worn down and no one ever told them what was actually going on.

So let me tell you what's actually going on. Starting with what I used to get wrong.

The Advice I Gave For Years (And Watched Fail)

When someone came to me with a cat spraying around the house, I gave them the standard playbook. The same handful of fixes you'll find everywhere.

Add another litter box. If you've got two cats, make it three litter boxes.

Scoop them more often, in case the other cat's scent in the box was setting it off.

Move the boxes to the spots the cat keeps marking.

Clean every spot with an enzyme spray so the smell doesn't draw them back.

And if none of that works, try a pheromone diffuser plugged into the wall.

It sounds reasonable. It's what most owners are told. And for a cat spraying out of territorial stress, almost none of it makes the slightest difference.

I just didn't understand that yet. So when it failed, I assumed the owner hadn't been consistent enough, or the cat was a difficult case. I kept giving the same advice and kept getting the same result.

Why They Kept Coming Back

What started to wear on me was how often I saw the same faces.

An owner would come in, I'd give them the same advice, and a few weeks later they were back. Nothing had changed. The cat was still spraying, the house still smelled, and they were more worn down than before.

By that point, most of them had been told the same two things sit at the end of the road.

Put the cat on a strong daily medication like fluoxetine or clomipramine, or start thinking about finding them a new home.

I heard versions of "I've tried everything and nothing works" so many times it stopped sounding like a complaint and started sounding like an accusation. Because they had tried everything. Everything I'd told them to.

I told myself this was just a hard problem. Some cases don't resolve. That's what I believed, right up until one that wouldn't let me keep believing it.

The Case That Made Me Stop And Think

A woman came in who had three cats, and one of them had been spraying for the better part of a year.

She'd done everything I would have told her to do. The extra boxes, the constant cleaning, the diffuser.

She loved that cat. And she sat in my office and told me, barely holding it together, that she thought she was going to have to give him up. That she couldn't see any other way out.

She'd already tried everything I would have told her to. And I had no idea what was left.

That was the moment it stopped being a hard case and started being a question I couldn't shake.

If everything we tell owners to do fails so often, maybe the problem isn't the owners. Maybe it's the advice.

What A Colleague Finally Made Me See

I took it to a colleague of mine, a specialist in feline behavioural medicine. I described the case, the pattern, all of it.

She wasn't surprised. She told me the reason my advice kept failing was simple. It was all aimed at the wrong thing.

Then she explained what spraying in a multi-cat home actually is. And once I heard it, I couldn't unhear it.

Why A Cat Marks A Home It Already Lives In

Here's the part almost no one gets told.

When a cat shares its home with another cat, some part of them never fully feels like the space is theirs.

It isn't about fighting. The cats can get along completely fine, sleep in the same room, groom each other, and it's still there underneath. Even cats that are perfectly friendly carry a low, constant sense of competition over territory.

Maybe it shows up as jealousy, maybe as wanting their own space, maybe as just needing somewhere that feels like theirs and theirs alone.

And when a cat feels that, they do the one thing that settles it. They lay down their scent to make the space feel like their own.

Behaviourists call this territorial marking, and it's driven by that underlying feeling, not by anything to do with the litter box.

In studies of multi-cat households, the more cats sharing a space, the higher the rate of marking, and it climbs with each cat added. A cat in a home with four or more cats is far more likely to spray than a cat living alone. That's not a coincidence. That's the whole cause in one statistic.

Something else worth knowing: a cat doing this often doesn't seem bothered at all. To them it isn't a big deal. It's just a small, normal thing they do to feel a bit more settled, and they've no idea it's a problem for you. It's why plenty of owners are surprised their cat is spraying when they otherwise seem fine.

Why Everything I'd Been Recommending Was Useless

Once I understood that, the failure of my own advice made total sense. Every piece of it was aimed at the surface, and the cause sat somewhere it never reached.

Adding boxes, moving them, scooping more. None of it touched how the cat felt about their territory, so none of it changed a thing.

The enzyme cleaner was worse than useless in one specific way. It lifts the smell for a day, but scrubbing their scent out of a spot is the exact thing that sends them back to re-mark it.

Owners are, without knowing it, resetting the problem every time they clean. I've watched people scrub the same corner for months, convinced they're helping.

Medication was the option I'd started to lean on, and it's the one I'm least proud of. It doesn't calm a cat, it sedates one. You get a duller, flatter version of your cat that often marks anyway, because the drug masks the feeling instead of removing it.

Roughly a third of cats don't respond to it for marking at all, and when you stop, the behaviour usually comes straight back. Most owners don't want their pet drugged just to get through the day, and I don't blame them.

Then there's the diffuser, and this is the one worth slowing down on, because the idea behind it is actually right.

A calming pheromone is genuinely what a cat like this needs. The problem is what's in most diffusers, and where it sits.

First, the scent. Not every diffuser carries the pheromone that actually settles this kind of cat. Plenty of owners tell me theirs did nothing at all, and that's usually why.

Second, and this is the real flaw, even the right scent is bolted to one wall in one room. A plug-in diffuser puts out a tiny radius. The cat has to be almost on top of it to get anything from it. And a cat doesn't spend its day sitting by a plug. They're roaming the whole house, marking in spots nowhere near it. You cannot settle a cat who moves through every room with something fixed to a single wall.

That was the realization that changed how I treat this. The calm can't sit on the wall. It has to be on the cat.

The Simple Fix I Recommend Now

If the calm has to travel with them, then it has to be worn.

That's what a pheromone collar does, and it's the first thing I reach for now. The one I use is called CalmKitty.

It carries the one pheromone that actually settles a cat like this, the same one a mother cat gives off to calm her kittens. It's the deepest signal there is for telling a cat's brain they belong and there's nothing to worry about, and cats respond to it from the day they're born.

Worn as a collar, that signal sits against them and travels into every room they go. It's with them wherever they feel the need to claim their space. They already feel at home, so the urge to mark never comes.

It's natural, it's drug-free, and it's gentle enough to wear around the clock. It won't change their personality one bit. It's the same cat, just a settled version of themselves. And it turns out that's all it takes for the spraying to stop.

In a clinical trial of 490 cats, the large majority showed a significant reduction in marking within the first week of wearing the pheromone collar. In my own practice, the pattern is just as clear. Owners who'd tried everything come back within days telling me the same thing.

It doesn't ease off. It doesn't get a little better. It stops, because for the first time the thing actually causing it has been dealt with.

The Change I Watch Happen

I've seen this go one way hundreds of times now.

Someone comes in ready to give up, completely out of options. A few weeks later they're a different person.

"I honestly thought we were going to have to give him up," one owner told me recently. "I still can't believe it was something this simple."

Another put it more plainly. "The spraying just stopped. My house actually smells decent now."

More than a few have told me the collar is the only reason that cat is still in their home. That's the part of this job I'll never get tired of.

Where To Get It (And Why It's Only Sold In One Place)

The CalmKitty collar normally sells for $64. Right now it's on sale for $48.

When you weigh that against what most owners have already spent, extra litter boxes, bottle after bottle of enzyme cleaner, a diffuser that ran over a hundred dollars on its own, the maths isn't complicated.

Each collar lasts a full 30 days, releasing that calming signal steadily the whole time, so your cat is covered around the clock without you doing a thing. If you'd rather not think about it again, you can subscribe for a fresh collar each month and drop the price to $40.

You'll only find the real CalmKitty collar on the official website, not in pet shops or big retailers. There's no middleman taking a cut, which is the only reason the price is what it is. Stock does move fast, and it has sold out before. If the page is showing it in stock while you're reading this, you're in time.

It's backed by a 30-day money-back guarantee. If it doesn't calm your cat and stop the spraying, you pay nothing.

If your cat is healthy but won't stop spraying, it was never bad behaviour, and it was never you not trying hard enough. You were just given advice aimed at the wrong thing. This is the one thing that deals with what's actually causing it.

Give your cat the calm that follows them, wherever they go.

Click the button above to check current availability.