I noticed that the one bad review I saw on here for this began with, "1st I gave my dog a bath" you should not give baths a few days before or after applying any topical flee medicine, despite what they say about being water proof, I believe they do wash off. I bath my pets as little as possible now that I am using spot on flee treatments. Secondly, if you still see flees "alive and well" after treatment that does NOT mean it's not working, it just means you have an infestation, and the flees in your house will continue to jump onto your pet until they too are killed. It can take 3 months or so to get a good handle on an infestation. I also recommend that if you DO have an infestation, reapply in 2 weeks after the 1st use, after 3 weeks the 2nd and 3rd use, and then go to the regular monthly schedule. I have lived through a severe infestation and this product saved my home and my pets. Also make sure to treat ALL the pets in your home! Take my tips in this review and you can't go wrong with this! it WORKS, we went from covered in flees, to NO flees. NOW in summer months, if your dogs go in and out, you will occasionally see a flee or two, this is normal and bound to happen with indoor/outdoor animals, but the good news is, you don't have to worry about it becoming a re-infestation. The medication will kill them off before that happens.