My dog is infested with fleas. I put this on after finding just one flea on her. It has been 2 weeks and she is scratching like crazy. I just checked her and pulled off about 50 fleas! And she is a small dog! I'm not happy with this product! I wish I didn't throw the damn receipt away or I would be using the guarantee they have! Oh and where we placed the product has also irritated my baby!