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My cat got Frontline spot-on, but I still see fleas. How long does it take to work?

Updated On September 23rd, 2025

Pet's info: Cat | British Shorthair | Male | unneutered | 1 year and 1 month old

Hello. I gave my one year old cat Frontline spot on for fleas yesterday and I have still seen no effect. How long do spot ons take to kill fleas and is Frontline effective?

1 Answer

Most Helpful Answer

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Answered By Ricardo Fernandez, DVM

Veterinarian, Veterinary Oncology Resident

Published on June 28th, 2019

Thanks for using Petco Pet Education Center, formerly Petcoach! Frontline is indeed effective. However, it may take a few days to see effect. Hopefully, it does work for Shadow. However, if no effect is observed, consider checking in with your veterinarian as other options could be attempted like Bravecto for example and even Capstar which has more of an immediate effect. Best of luck!

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