There are a wealth of treatment options for the eradication of fleas in animals. Some are discussed here. Before buying and using any product, you must check that it is suitable for your pet. Some dog treatment can be harmful to cats for example.
Following the discovery of fleas, an initial treatment of your pet should be carried out whichever further treatment option you choose. This involves thoroughly combing through the hair or fur of your pet with a fine tooth comb. Exposed on the comb along with loose fur you will also pick up the eggs and some fleas too. Pull these off and put straight in a bowl of warm water which will drown the fleas. This is much easier than drying to squash them however manually dextrous you are. Once this process has been finished, flush the content of the bowl down the toilet.
This can be a great option for cats that live predominantly outdoors. They are cheap but some can irritate the neck of the animal. It is also a good idea to make sure that they provide some give. Indeed, some brands will be slightly elasticated. Otherwise, there is a chance of strangulation if say the cat got it snagged on the branch of a tree.
Topical sprays, powders and shampoos
These all contain an insecticide and sprayed, combed in or shampooed in as the type suggest. The powder is not the most effective, as it can be hard to ensure it reaches down on to the skin of the animal where the eggs lay rather than remaining amongst the hairs. The other two methods, spraying and using shampoo, are not two of the most favourite activities for a cat, so it can be hard to persuade them to come anywhere near you when you try for a second dose.
Flea bombs or flea foggers
These act by giving releasing an airborne insecticide powder when set off. They are not used to treat the animal but rather the environment where they live. Although effective, they involve covering your house with a film of harmful powder. Precautions need to be taken in relation to contamination of food and water for example.
It is often advised that two or more of these options are used in concert. The use of flea bombs in your home in conjunction with combing your cat then fitting a flea collar or treating with shampoo/spray is likely to prove more effective than just one of these used in isolation.