Manufacturers on the other hand insist that this is not the case, and that properly used, in accordance with the instructions on the packet, these flea control products are as effective as they have always been - but of course, they would say that wouldn't they?

So who do you believe? I've spent considerable time researching the available data, and it appears that at this time, there is no evidence that fleas are in fact developing a resistance to these types of products. The evidence in support of this includes:

• research (admittedly from manufacturers) which indicate that while it is not that fleas could not develop resistance to these products, there is no clinical evidence that they have in fact actually developed resistance.

• Evidence (both clinical and anecdotal) that changing brands doesn't seem to solve flea infestation problems (which it should do, if the flea had developed resistance to a particular product)
  

• Anecdotal evidence that often one pet in a multi-pet household suffers from fleas more than the other - if it was the fleas that were resistant to the products, surely all the pets would have a problem.
  

On that basis, it appears that the best view at this time is that the existing leading brand monthly topical flea control products (including Frontline Plus, Revolution, Advantage, Advocate and Advantix) remain the best form of treatment for the control of fleas in dogs and cats currently available if used properly and in conjunction with taking steps to control fleas in the pets environment.