Started using Frontline Plus 6/12/10. The label states that it kills fleas, flea eggs, and flea larvae for up to 6 weeks. It also states that it prevents development of all flea stages for up to 6 weeks. Noticed lots of flea eggs and fecies on a glass top table the cats like to lay on during this first treatment period. On 7/11 I swepted some flea eggs and flea dirt from the table into a petri dish to see if the eggs would hatch. Like a fool I administered a second topical dose at the recommended 4 week period on 7/12. I called the company (Merial) on 7/26 to ask if they had a problem with one of their lots because it didn't seem to be working. They said there was no problem. I also told her that the egg sample hatched into larvae and the label said it kills flea eggs. I got some lame just give it time excuse. I also asked about side effects and was told there were no behavioral effects (which I have since learned is not true). All in all I hatched 4 broods of eggs. Called about getting my money back 8/24 (Satisfaction Guarenteed also on the label) and all they were interested in was the adverse effects (needs to be reported to EPA). She said they weren't medically trained and someone would call back within 24 hours to get more details on the adverse effects and to discuss a refund. I switched to another product and within 12 hours I found 27 dead fleas (that's only what I found) and there are no longer flea eggs and dirt on the table. I now have tens of thousands of viable flea eggs in my house because Frontline lied about their product-not to mention the effects on my cats and of course..no refund. SIX days later I received a call (the 24 hr call) from Merial rep who only wanted to discuss side effects, got very huffy as i kept bringing up the fact that eggs hatched, and that I wanted a refund and I ended up hanging up on her. People spend millions on this product. Meanwhile I have tens of thousands of viable flea eggs in my house. THIS PRODUCT DOES NOT WORK AS LABELED. A consumer ripoff at it's finest.