Cat spraying after new kitten arrived

A 9-year-old Russian Blue who's started spraying after a new kitten arrived — that's a classic territorial stress response, and it tells you your older cat is genuinely overwhelmed, not just being difficult. Russian Blues are sensitive, quite bonded to their routines, and don't take well to sudden household changes. The spraying is communication: he's trying to reassert ownership of his space. Cat anxiety is real and often further along by the time you see it this obviously — hiding stress is what cats do, so spraying is actually a late signal. Before I point you toward what's worked well in this situation, can you tell me a bit more? How long ago did the kitten arrive, where is your Blue spraying specifically, and are they having any direct contact yet or still separated?

That timeline makes complete sense. Three weeks in, two weeks of shared space — your Blue hasn't settled, and the hissing and chasing confirms he still sees the kitten as a threat rather than a housemate. The living room spraying is significant: that's his core territory, the space he's most invested in protecting. The good news is this is very treatable if you address the underlying stress signal rather than just cleaning the spray sites. What I'd recommend here is the Feliway Classic Starter Kit — the plug-in diffuser, not the spray. The synthetic F3 pheromone it releases mimics the facial marking cats do when they feel secure in a space. It won't sedate him or change his personality, but it takes the edge off the alarm state he's stuck in. Plug it into the living room, which is exactly the right location given where he's spraying. One diffuser covers up to 70 square metres and lasts about a month. Most owners see a reduction in spraying within two to three weeks, though some cats respond faster.

Both, typically — because both are coming from the same place. The spraying and the aggression are different expressions of the same anxiety. As the diffuser brings his baseline stress level down, the reactive behaviour usually softens alongside it. You probably won't get to zero hissing quickly — that's about the relationship between the two cats, which takes time — but the intensity and frequency should reduce noticeably. One thing worth doing in parallel: make sure your Blue has at least one space the kitten genuinely cannot access. A room, a high shelf she can't reach yet, somewhere he can decompress without having to defend it. That matters as much as the pheromone product. The diffuser reduces the chemical alarm state; the safe space reduces the practical one.

Start with just the living room — that's where the behaviour is concentrated and where he clearly feels most under threat. One diffuser used consistently in the right location will outperform two used haphazardly. If after three to four weeks you're still seeing spraying in another room, add a second unit there, but most households with this specific scenario find one well-placed diffuser is enough. The Feliway Classic Starter Kit on Amazon UK is straightforward — it comes with the diffuser unit and a 48ml refill, which is one month's supply. After that the refills are sold separately and are reasonably priced.

Good — I think you'll see a difference within a couple of weeks. Just make sure it stays plugged in continuously rather than switching it off at night, which is a common mistake that interrupts the pheromone level in the room. Clean the spray sites with an enzymatic cleaner before you start too, so the residual scent markers aren't reinforcing the behaviour. If things haven't shifted meaningfully after six weeks, it's worth a conversation with your vet about whether there's anything else going on — but this approach works well for the scenario you've described.