Any of the topical flea treatments from your vet should work and I’ve heard the Revolution pill works very well but haven’t tried it. Do not buy the "over the counter" flea treatments - such as in the pet section of Walmart or the grocery store for instance, as they do not work and may be more dangerous for your cat. Flea collars do not work. A very good source for the good treatments such as Frontline, Advantage, Revolution, and Advocate is Ebay. I've found it to be much cheaper than the vet.
A note about flea tolerance to poison....people are noticing that American fleas are becoming tolerant to Frontline. Advantage brand, however, uses a poison that was unknown in America 10 years ago. Therefore, if you notice live fleas after one treatment of Frontline, switch to Advantage. Advantage is also cheaper than Frontline.
Source(s):
6 years experience in cat rescue and fostering