Flea control for cats comes with a warning that owners of both species must take seriously: many dog flea-and-tick products are toxic, sometimes fatally, to cats. Each year cats are poisoned because a well-meaning owner used a leftover dog spot-on or let a treated dog groom the cat.
The permethrin problem
Many dog spot-on products contain permethrin at concentrations cats cannot metabolise. In a cat it can cause tremors, seizures and death within hours. Even a small amount — from licking a treated dog or rubbing against them — is dangerous. If a dog product ever gets onto a cat, wash it off and call your vet immediately.
What to use instead
- Only ever use a product clearly labelled for cats and dosed for their weight.
- Ask your vet to recommend a cat-specific spot-on, tablet or collar.
- In multi-pet homes, keep treated dogs separate from cats until the application is fully dry.
Do indoor cats need it?
Often, yes. Fleas hitch a ride indoors on shoes, on other pets, and through windows. An indoor cat with a sudden scratching habit or flea dirt in the coat needs treatment too. Talk to your vet about a sensible year-round plan rather than reaching for whatever is in the cupboard.
