depending where you are in the uk you can now get front line from pets at home and if you are in the south pampurred pets. but some people say frontline is not that strong now, there is another one but cant think of the name. also you can get johnsons 4 fleas which is really good if you have a big problem, as you can use them and use a drop at the same time. the j4fleas start working in 15 mins and will kill all fleas and eggs within 24 hours, which gives you a head start when defleaing them.