
This product has worked very well on fleas for our golden retriever. We do not bathe him between treatments, even though some pet shampoos claim they won't remove the product-- we don't take any chances. I did NOT have success with their other product ADVANTIX for ticks. Only FRONTLINE worked for ticks, but was worthless for fleas! So I stick with advantage most of the time and it does a great job on fleas. I would guess that the previous reviewer might have an infestation problem in their house, so the dogs are constantly being exposed to new fleas, and I believe it takes 24 hours for the product to kill them. I have also heard that fleas in certain areas are becoming resistant to the treatments, and perhaps that is what is going on with them.Get more detail about Advantage - Blue Box for Dogs over 55 pounds - 6 pack.