"I purchased these drops for my cat after having an unsuccessful use of other, "natural" flea and tick drops. After only a few hours, my cat is noticably more relaxed, scratching less, and yes, I have found some fleas.... but the fleas are all dead or dying. The other drops did not have this effect at all. Additionally, I feared that the drops may have a strong medicinal odor, but actually found them very tolerable. Thank you, Advantage! I would highly recommend this product to anyone with a flea/tick problem."