Update from previous post - I gave my cat a frontline plus treatment around 3 and a half weeks ago now due to discovering he had fleas, after around two weeks of combing his coat through, using flea shampoo as advised by my vet it seemed as if they went, however I noticed he's still itching alot at the back end I combed him through again and found 9 fleas and alot of eggs. I've used frontline plus now for around 2 years and it's always worked.