Flea treatment for dogs and cats in one house

Five rescue cats and a Greyhound — that's a wonderful house but a genuinely tricky flea situation, because you're coordinating across two species with very different safe product lists. The big thing to know upfront: 95% of fleas aren't on any of your animals right now — they're in your carpets, bedding, and soft furnishings — so treating the home is just as important as treating the pets. A single product won't cover both, and some dog flea treatments contain permethrin, which is lethal to cats, so that's something we'll need to be careful about here. Can you tell me how big your Greyhound is, how bad you'd say the infestation is right now (a few fleas spotted vs. everyone scratching constantly), and have you done anything to treat the home yet?

That instinct to pause and check first is exactly right — permethrin-based spot-ons are very effective on dogs but genuinely dangerous in a cat household, so you've done well not to grab the first thing off the shelf. For a 30kg Greyhound in a multi-cat home, I'd recommend Bravecto Spot-On for Dogs (large dog, 20–40kg). It's a single application that kills fleas and ticks for up to 12 weeks, it contains fluralaner rather than permethrin, and once it's dry on the dog it poses no contact risk to your cats. It's available on Amazon UK and works fast — you'll see a significant flea drop within 8–12 hours. One important note for Greyhounds specifically: they can sometimes be sensitive to certain medications, but Bravecto has a well-established safety profile and fluralaner is not one of the compounds that causes issues in sighthounds. Can I ask — are your cats already on a flea treatment, or do they need sorting too?

Okay, so you need a full three-part plan: the dog, the cats, and the home — all done around the same time, otherwise they'll just keep reinfesting each other. For the cats, the safest and most effective option is Advantage spot-on for cats, which is imidacloprid-based and completely safe alongside Bravecto on the dog. You'll need the right weight band for each cat — Advantage comes in under 4kg and over 4kg versions, so check your cats' weights if you can. For the home, Indorex Defence Household Flea Spray is the gold standard — it kills adult fleas and contains an insect growth regulator that stops eggs and larvae developing for up to 12 months. You'll need to hoover thoroughly first, then spray carpets, skirting boards, under furniture, and all soft furnishings. Keep cats and your Greyhound out of each room until it's fully dry. With five cats, a dog, and a bad infestation, doing all three on the same day or within 48 hours will give you the best chance of breaking the cycle quickly.

It's a fair concern, especially with five cats. Indorex is safe once dry — the active ingredients (permethrin and pyriproxyfen) settle and bond to fibres, so the risk is in the wet spray phase. The key rules are: ventilate well while spraying, keep all pets and people out until every treated surface is completely dry (usually 30–60 minutes with windows open, longer in a cool or damp room), and don't spray anywhere cats eat, drink, or where you keep their food bowls. Don't spray it directly onto cat bedding they'll be sleeping on that same day — wash that separately at 60°C instead. Once dry, it's been used safely in cat households for years. Given the scale of what you're dealing with, the risk of not treating the home is honestly higher than the risk of using it correctly.

Exactly right. Bravecto Spot-On for Dogs (20–40kg) for your Greyhound, Advantage spot-on in the correct weight band for each of the five cats, and Indorex Defence for the home — ideally all within the same 48-hour window. After that, the main thing is not to panic if you still see a few fleas in the first couple of weeks. Eggs already in the carpet will hatch and the newly emerged adults will die when they hit the treated pets, but it can look like it's not working at first. Stick with it, re-hoover regularly, and you should see things calm down significantly within 3–4 weeks. You've got this.